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Wrongful Conviction Series

October 26, 2022



A 17-year-old boy is accused of a triple homicide. He purportedly gave a written statement to police in broken English, admitting that he possessed a knife which the State’s serologist swears  contains  one  of  the  victims’ blood. The serologist testified that the other weapons, an axe and knife, also contained the hair and blood of the victims. A college student testified for the State that he supplied the weapons, agreed to trash a house, and drove his co-defendants to the crime scene. The police recovered the weapons from this college student’s home.

However, the blood on the murder weapons is not that of the victims’ at all. It is animal blood. Latent fingerprints lifted from the murder scene have been destroyed or lost. Worse yet, the State suppresses the fact that its expert witness likely perjured himself. In fact, the weapons have been tampered with and most likely have never been tested at all. This is a true story. The defendant was my client who was on death row and came within two days of execution.  His case is the first death penalty case in which the State of Texas confessed error.

What brought the State around?  And more importantly, how did I know that the State’s blood expert was lying.


A 1996 Department of Justice study reported twenty-eight persons were released from prison as a result of post-trial DNA testing. Convicted by Juries, Exonerated by Science: Case Studies in the Use of DNA Evidence to Establish Innocence After Trial, p. 2. The State’s expert witness in four of these cases was Fred Zain. Even though Fred Zain was discredited by the West Virginia Supreme Court, and was tried on charges of theft of services based upon his routinely perjurious testimony.  Texas once defended convictions supported by his testimony and no office undertook a review of his cases.

My point is, I did not know the State’s expert was lying about the blood evidence in Miguel’s case. This is why defense lawyers cannot afford to rely upon the prosecution to reveal discovery, or count on local forensic labs to provide competent forensic testing.  Nor should Courts accept hair and fiber comparison, serology, RFLP, DNA, fingerprint, voice spectrographs, mass gas spectrometry and pathology, among other matters at face value. The scientific community’s interest in evolving science coupled with law enforcement’s often competitive effort to ferret out crime; sometimes produces misconduct or mistaken information in crime labs or law enforcement agencies. Why is this so? The United States Supreme Court offered a partial explanation.


The Court found that our system of justice requires integrity of evidence and finality to function properly and efficiently.  But the Supreme Court observed that science has a different goal than that of the criminal justice system. Science seeks to test a number of hypotheses with the truth only eventually surfacing. It is ever evolving and accepts that accepted principles will change with evolving knowledge.  Therefore, the Supreme Court held that trial and appellate courts must intervene as gatekeepers conserving scientific evidence.

“Scientific conclusions are subject to perpetual revision. Law, on the other hand, must resolve disputes finally and quickly. The scientific project is advanced by broad and wide-ranging consideration of a multitude of hypotheses, for those that are incorrect will eventually be shown to be so, and that in itself is an advance. Conjectures that are probably wrong are of little use, however, in the project of reaching a quick, final, and binding legal judgment often of great consequence about a particular set of events in the past. We recognize that, in practice, a gate keeping role for the judge, no matter how flexible, inevitably on occasion will prevent the jury from learning of authentic insights and innovations. That, nevertheless, is the balance that is struck by Rules of Evidence designed not for the exhaustive search for cosmic understanding but for the particularized resolution of legal disputes.” Daubert v. Merrill Dow Pharmaceuticals, 509 U.S. 579, 597 (1993)[emphasis added].

Thus, the Court, not the expert, must assure that an evolving hypothesis is not presented to the jury as science that will stand the test of time.

The Supreme Court held that today’s trial courts have a duty to act as gatekeepers regarding the scientific and experiential expert evidence. The Court rejected the predominantly applied Frye general acceptance test for admissibility and replaced it with a rigorous relevancy test. See Rules 401 [relevancy] and 702 [expert testimony] Federal Rules of Evidence. See also Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed 2d 469 (1993). And it charged courts with assessing the validity of the evidence and rejected courts relying upon what is generally accepted in the community from which the evidence originated.

But this is how most Courts still assess scientific and other expert evidence.  Most Courts ask “Have you qualified as an expert before now?”  and “Has a Court admitted this sort of evidence before this case?” and then the Court admits the opinion testimony in evidence.  But, this is the rejected “general acceptance” Frye test that has been widely discredited.

As a result, the Scientific Community approached the National Academy of Sciences for help to improve science used in Courts. The NAS formed a committee of judges, statisticians, professors, lawyers, doctors, medical examiners and other experts to study the present and future resource needs of the forensic science community, including state and local crime labs, medical examiners and coroners. The NAS committee studied the forensic science disciplines and concluded that all areas of forensic science other than DNA[1], lacked validation and often failed to reveal uncertainties and bias.  Most accepted science was not reliable.  The NAS concluded that such unreliable information is not a proper foundation upon which to support final conclusions in criminal cases.  Instead, this reliance results in wrongful convictions.  The NAS also concluded that forensic science needs oversight, judges need training, and that the coroner system should be abolished.

“The simple reality is that the interpretation of forensic evidence is not always based on scientific studies to determine its validity. This is a serious problem. Although research has been done in some disciplines, there is a notable dearth of peer-reviewed, published studies establishing the scientific bases and validity of many forensic methods.”

Bottom line, most scientific evidence presented as reliable is not.  It has not even been proven as valid in most fields.  Simply, the science is bad.   A second and third question are steps in this gatekeeping function.   In addition, to (1) is the science bad or unreliable?, the Court must determine (2) Is the witness qualified?, and (3) Was the scientific process performed correctly in this case? The only way that this can be established is through the Trial Court’s gatekeeping function.  And if the Trial Court fails to do this, the Court of Appeals must ensure this.


The Trial Court must determine the admissibility of such evidence, preliminarily, outside the presence of  the  jury.  Texas  Rule  of  Evidence 104, provides:

  • In General. The court must decide any preliminary question about whether a witness is qualified, a privilege exists, or evidence is admissible. In so deciding, the court is not bound by evidence rules, except those on privilege.
  • Conducting a Hearing So That the Jury Cannot Hear It. The court must conduct any hearing on a preliminary question so that the jury cannot hear it if:
    • the hearing involves the admissibility of a confession in a criminal case;
    • a defendant in a criminal case is a witness and so requests; or
    • justice so (emphasis added)

On remand in Daubert, the Ninth Circuit described the serious inquiry which trial courts deciding admissibility of expert opinion evidence must conduct.

Federal judges ruling on the admissibility of expert scientific testimony face a far more complex and daunting task in a post- Daubert world than before. The judge’s task under Frye is relatively simple; to determine whether the method employed by the experts  is  generally  accepted   in   the   scientific  community. Under Daubert, we must engage in a difficult, two- part analysis. First we must determine nothing less than whether the experts’ testimony reflects scientific knowledge, whether their findings are derived by the scientific method, and whether their work product amounts to good science. Daubert v. Merrell Dow Pharmaceuticals, 43 F.3d 1311, 1315-1316 (9th Cir. 1995), cert. denied, 116 S.Ct. 189 (1995).

The Frye test was backward looking, but post-Daubert, Courts must look forward. What is the current state of the science?  It is not correct to admit scientific evidence based upon the fact that prior courts in prior reported cases admitted similar evidence.  If a Court simply admits scientific evidence because that kind of science has been admitted before, this is the improper application of the old rejected Frye test. The courts must determine the validity of the science used in each particular case by determining if the methodology supports the science and if it was applied accurately.[2]

Step One:   Is the science valid?

Checklist:  Does the expert opinion neglect scientific knowledge?

 Are the findings of the witness derived from the scientific method?  This step includes a determination that the results are reliable.

 Whether the witness’ work product is good science.

The NAS committee’s report also found that judges were not adequately trained to make the admissibility determination. This has led to the unintended result that, if the judge does not understand the science, the evidence is going to be admitted.


The Courts’ proper decisions concerning the admission of scientific evidence are reviewed under the highly deferential abuse of discretion standard. General Electric Co. v. Joiner, 522 U.S. 136, 118 S.Ct. 512, 139 L.Ed.2d 508 (1997)[rejecting evidence of animal studies as probative of human reactions]. But this inquiry is broader under Texas Rule of Evidence 702.  The rule questions whether the testimony will assist the trier of fact. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed 2d 469 (1993). Under this rule, the evidence must be relevant, reliable, and must be helpful. The Supreme Court used, as an example, evidence of the phases of the moon. Such evidence is admissible to show whether it was light or dark on a particular evening.  However, this same evidence was not admissible to show whether individuals were acting peculiarly on a particular evening. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 591-92 (1993).

Therefore, Courts must exclude scientific and other expert opinion evidence if it is not proven by a preponderance of the evidence to be relevant, reliable, and helpful to the jury. If evidence is beyond the ken of lay jurors, then the court is charged with determining its reliability as a guard against the admission of junk evidence. A timely defense challenge is necessary to give rise to the Court’s gatekeeping duty.  Ex Parte Diversey Corp., 742 So.2d 1250, 1254 (Ala. 1999)[defense did not challenge testimony, thus, it was not error for court to admit it]; Questar Pipeline Co. v. Grynberg, 201 F.3d 1277 (10th Cir. 2000).

Since judges are given broad discretion under a flexible standard of admissibility, litigants rely on judges to assure quality and competent evidence. But lawyers and judges lack the scientific expertise necessary to comprehend and evaluate forensic evidence in an informed manner. Trial judges must decide the admissibility of such evidence alone, without input from colleagues and with little time for research and deliberation. Thus, judicial review does not solve problems with subjective, unreliable, and unvalidated science.

The Court of Criminal Appeals held in Kelly v. State, 824 S.W.2d 568,

573 (Tex. Crim. App. 1992) that courts should determine the validity of scientific theories by determining: “(1) acceptance by the relevant scientific community, (2) qualifications of the expert, (3) literature concerning the technique, (4) the potential rate of error of the technique, (5) the availability of other experts to test and evaluate the technique, (6) the clarity with which the underlying theory or technique can be explained to the court, and (7) the experience and skill of the person applying the technique.”


In Ex parte Overton, 444 S.W.3d 632 (Tex. Crim. App. 2014), Judges Meyer and Cochran performed the gatekeeping role in a writ of habeas corpus decision in the majority and concurring opinions, reversing the case. They evaluated the expert testimony provided by doctors with different qualifications in a complex medically dense case. Judge Cochran spoke of the testimony from physicians regarding the decedent’s pre-existing developmental problems, the cause of death, and the significance of the decedent’s first unadulterated emesis collected at a medical facility. When the case was first sent to the trial court for a hearing on the writ, Judges Cochran, Price and Johnson wrote that science and just verdicts are disconnected since science will not always stand the test of time.

“This disconnect between changing science and reliable verdicts that can stand the test of time has grown in recent years as the speed with which new science and revised scientific methodologies debunk what had formerly been thought of as reliable forensic science has increased. The potential problem of relying on today’s science in a criminal trial (especially to determine an essential element such as criminal causation or the identity of the perpetrator) is that  tomorrow’s science sometimes changes and, based upon that changed science, the former verdict may look inaccurate, if not downright ludicrous. But the convicted person is still imprisoned. Given the facts viewed in the fullness of time, today’s public may reasonably perceive that the criminal justice system is sometimes unjust and inaccurate. Finality of judgment is essential in criminal cases, but so is accuracy of the result—an accurate result that will stand the test of time and changes in scientific knowledge.” Ex Parte Overton, 2012 Tex. Crim. App. Unpub. Lexis 85, at p. 6 (Tex. Crim. App. February, 8, 2012).

The judges also explained that scientific evidence questions also included cases where the scientific testimony was not fully informed and did not take into account all of the scientific evidence that was available. See id.

Subsequently, when the case was reversed for a new trial, the majority opinion compared the testimony of a less qualified, less knowledgeable medical doctor with the preeminent expert on salt intoxication.

“Dr. Moritz was an extremely well-qualified expert on salt intoxication, as evidenced by the discussion during his testimony about his career path, research, and published papers. In his deposition, he was knowledgeable and able to explain complicated medical concepts with ease. During his testimony, he not only refuted much of what Dr. Rotta testified to for the State, but also established that he was better informed on the subject of salt intoxication than Dr. Rotta. Further, Dr. Moritz testified that A.B.’s survival, regardless of when he was brought to the hospital, would have been determined largely by luck. He described the mortality rate with salt intoxication as very high and said that it was extremely unlikely that A.B. would have lived, irrespective of how quickly medical care was given. Because the jury convicted Applicant based on a theory of failing to provide A.B. with adequate or timely medical care, this testimony goes directly to the verdict rendered in her trial.” Ex parte Overton, 444 S.W.3d 632, 641 (Tex. Crim. App. 2014).

The concurring opinion performs a much more detailed analysis of Dr. Moritz’s qualifications and expertise and together the opinions provide an excellent example of the gatekeeping function. Not just any medical doctor will  do, and not just any methodology can be accepted. A valid scientific methodology must be used and an adequately qualified expert must employ it. The function is a forward looking (what is the science today?) case, science and scientist specific inquiry. In Ex parte Overton, supra, the Court of Criminal Appeals engaged in gatekeeping as the decision maker in an original writ. It explored the depths of the science and the scientific research to make its determinations about the crucial nature of Dr. Moritz’s testimony and its superior materiality over that of a less qualified and informed physician who testified for the State.

To recap, the gatekeeping performed by a trial court, to be accorded any deference, must include a forward looking independent analysis of whether the scientific method employed in that case is currently valid. It must also include a determination that the question to be determined is one with which the fact finder

requires assistance. In addition, the court must also determine if the expert witness is adequately qualified and adequately informed about the facts and the science to render an opinion.[3] And that qualified expert must also employ the correct valid scientific methodology correctly.

So often in criminal cases, the medical examiner who lacks experience in the area of medicine involved parrots the conclusion of a physician who also lacked the qualifications and expertise of a case, parrots the opinion of law enforcement.  In Overton, Dr. Rota mistook ordinary symptoms of hypernatremia as child abuse.  He lacked any experience with hypernatremia.


Thus, Courts have to protect against these mistakes at the pre-trial stage and look critically at expert testimony.  The result is that Trial Courts are charged with becoming sufficiently proficient regarding each area of specialized knowledge to accurately assess whether the evidence is reliable and helpful to the jury, assuring the integrity of the process. As a practical matter, however, each of you must become adept at determining the type of science or expert evidence involved in a case and obtaining sufficient assistance to evaluate the evidence. All of this information must be gleaned from the record. If a part of the gatekeeping function has not been performed, the decision of the trial court is not afforded deference, but is reviewed de novo. This is because the gatekeeping function has not been correctly conducted as a legal question.

“Under Daubert, we must engage in a difficult,  two-part  analysis. First we must determine nothing less than whether the experts’ testimony reflects scientific knowledge, whether their findings are derived by the scientific method, and whether  their  work product amounts to good science. Second, a court must ensure that the proposed expert testimony is relevant to the task at hand, i.e., that it logically advances a material aspect of the proposing party’s case. The United States Supreme Court refers to this second prong of the analysis as the ‘fit’ requirement.” Daubert v. Merrell Dow Pharmaceuticals, 43 F.3d 1311, 1315-1316 (9th Cir. 1995), cert. denied, 116 S.Ct. 189 (1995).

The Federal Judicial Center published a guide to assist federal judges in this difficult task. Although judges may desire to allow lawyers to try their cases unencumbered by judicial interference, the Daubert, supra, Kumho Tire, supra and Joiner, supra, cases require them to make an independent inquiry regarding any testimony requiring specialized knowledge and filter out that which is unreliable and unhelpful.

‘With respect to the role of the trial judge, Daubert is quite explicit. Judges must be more active in screening expert scientific testimony, hence the notion of judges as gatekeepers. Are most judges adequate to the task? In the view of certain commentators, judges, despite their general enthusiasm and diligence tend to be highly resistant to the sort of learning Daubert demands. Walsh, Judge Joseph        T.,        Keeping        the        Gate,        83    Judicature 140 (November/December 1999). See also, J.R. Mrsookin. Expert evidence, partisanship and epistemic competence. 73 BROOK L. REV. 1009, 1033 (2008) (‘[S]o long as we have our adversarial system in much its present form, we are inevitably going to be stuck with approaches to expert evidence that are imperfect, conceptually unsatisfying, and awkward. It may well be that the real lesson is this: those who believe that we might ever fully resolve-rather than imperfectly manage- the deep structural tensions surrounding both partisanship and epistemic competence that permeate the use of

scientific evidence within our legal system are almost certainly destined for disappointment.’).”

Utilizing the NAS Committee report helps identify most forensic evidence is unreliable and should not be admitted until it is validated and the scientist performing the testing is determined to be qualified and proficient for each case.

“The adversarial process relating to the admission and exclusion of scientific evidence is not suited to the task of finding ‘scientific truth.’ The judicial system is encumbered by, among other things, judges and lawyers who generally lack the scientific expertise necessary to comprehend and evaluate forensic evidence in an informed manner, trial judges (sitting alone) who must decide evidentiary issues without the benefit of judicial colleagues and often with little time for extensive research and reflection, and the highly deferential nature of the appellate review afforded trial courts’ Daubert rulings. Given these realities, there is a tremendous need for the forensic science community to improve. Judicial review, by itself, will not cure the infirmities of the forensic science community. The development of scientific research, training, technology, and databases associated with DNA analysis have resulted from substantial and steady federal support for both academic research and programs employing techniques for DNA analysis. Similar support must be given to all credible forensic science disciplines if they are to achieve the degrees of reliability needed to serve the goals of justice. With more and better educational programs, accredited laboratories, certified forensic practitioners, sound operational principles and procedures, and serious research to establish the limits and measures of performance in each discipline, forensic science experts will be better able to analyze evidence and coherently report their findings in the courts. The current situation, however, is seriously wanting, both because of the limitations of the judicial system and because of the many problems faced by the forensic science community.” Strengthening Forensic Science In the United States: A Path Forward [emphasis added].

However, accreditation is not a panacea. The FBI Lab sought and obtained accreditation after Frederick Whitehurst first whistle blew the lab’s failings in 1994. But in 2015, we again heard about thousands of cases where the FBI lab, and State labs and scientists trained in the FBI lab, used invalid hair microscopy evidence that has since been discredited. The testimony and reports in the cases were flawed and some fourteen people had died or been executed based on this flawed testimony.  Many state courts mistakenly still admit such testimony in evidence today.


The United States Supreme Court held in Daubert that Rule 702 of the Federal Rules of Evidence applies to all expert testimony, not only that which is novel.

“Although the Frye decision itself focused exclusively on novel scientific techniques, we do not read the requirements of Rule 702 to apply specially or exclusively to unconventional evidence.” Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 125 L.Ed.2d 469, 482 n. 11 (1993).

The Supreme Court further explained in Kumho Tire Company v. Carmichael, 119 S.Ct. 1167, 1171 (1999), that the trial court’s gatekeeping function announced in Daubert applies to testimony based upon technical and other specialized knowledge in addition to scientific testimony. Kumho Tire, supra, is a products liability case that concerns opinion testimony regarding tire defects.

The key objective is that all expert and lay opinion testimony must be subjected to the same rigorous, pre-admission consideration. “Expert” and lay opinion testimony has the most significant impact in criminal cases because it is characterized as objective, dispassionate and more informed that that of fact witnesses and the litigants. It is characterized as unbiased.

However, this is far from the case. Courts, when considering whether the scientific methodology is correct, must be alert to flaws outside of science that are injected into and infect the process. For example, testimony that is informed by police reports, is biased by the police theory, is influenced by subjective analysis, or which flaws or shortcomings (error rates) are not revealed or admitted by the witness in cross-examination. The prosecution and Courts cannot rely on the experts to get it right or to take on faith that the opinion of the lab scientist is correct. How often have you heard a Court explain that it did not order expert witness funds to test the same evidence that the prosecution has tested because  “that evidence has already been tested. I am not going to pay to have it tested again”? So, because of this culture of “trust” of scientists or experts that we do not understand, we often mistakenly accept unverified forensic science at face value. For verdicts to stand the test of time, to be scientifically valid, we cannot trust the science, we must learn it and confirm it.

In Hinton v. Alabama, 571 U.S. 263, 134 S.Ct. 1083 (2014), the United States Supreme Court held that defense counsel is ineffective if he or she hires an unqualified expert to rebut the State’s expert on firearms and toolmarks evidence.  It was unreasonable for the lawyer to fail to seek additional funds to hire a qualified expert.  The Court referred to its earlier opinion in Harrington v. Richter, 562 U.S. 86 (2011) where the Court held that when the only reasonable and available defense strategy requires consultation with experts or introduction of expert witness testimony, counsel is ineffective in not obtaining an expert witness for the defense.  Thus, the Court recognizes that defense experts are necessary to provide effective assistance of counsel.

The National Association of Criminal Defense Lawyers distinguished defense lawyers’ roles from that of prosecutors and took a stand regarding the subjective forensic science that has yet to be validated. No such evidence should be admitted in evidence against the accused until it is validated. If, over objection, it is admitted, all of its flaws should also be introduced and explained to the jury.

“The United States Supreme Court cautioned a generation ago that the “[e]xpert evidence can be both powerful and quite misleading because of the difficulty in evaluating it”. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 595 (1993)

The recognition of deficiencies with forensic evidence, was only grown since then. See Melendez-Diaz v. Massachusetts 557 U.S. 305, 129 S.Ct. 2527, 2537, 174 L.Ed.2d 314 (2009) [“Serious deficiencies have been found in the forensic evidence used in criminal trials…”].

“[T]he legal community now concedes, with varying degrees of urgency, that our system produces erroneous convictions based on discredited forensics” Id.

“Nonetheless, the prevalence of forensic evidence in criminal cases has grown over time. In this era of increasing reliance on forensic evidence, defense lawyers, more than ever, need to have the ability

to understand such evidence to effectively represent the accused and to ensure that every defendant is afforded due process of law. When it is the defense counsel who considers the affirmative use of forensic evidence- whether to provide reasons for the jury to doubt the prosecution’s charges or even to fully exonerate the defendant- defense lawyers, consistent with their sixth Amendment and ethical obligations, need independent access to scientific and forensic experts and evidence to prepare and present the defense. In the more frequent instances in which it is the prosecution that seeks to use forensic evidence to carry its burden to prove beyond a reasonable doubt that a criminal defendant committed a crime, defense counsel is constitutionally and ethically obligated to ensure that the evidence is sufficiently accurate and reliable to be presented to a jury and that, if it is so presented, that the jury understands the limits of the evidence.” Principles and Recommendations to Strengthen Forensic Evidence and Its Presentation in The Courtroom, p.2 (NACDL February 27, 2010).

“Not all forensic disciplines are equally grounded in validated science. Nor are all forensic processes within a particular discipline equally grounded in validated science. The results of any forensic theory or technique whose validity, limitations, and measures of uncertainty have not been established should not be admitted into evidence to prove the guilt of an accused person..   Prior admissibility or use of the results of a forensic discipline, techniques, or theory is not conclusive proof of validity or reliability.” Principles and Recommendations to Strengthen Forensic Evidence and Its Presentation in The Courtroom, p.8 (NACDL February 27, 2010).

For too long prosecution “experts”, merely voicing their subjective and absolute views, testified by essentially saying, “believe me, he’s guilty.” In innumerable areas, they have passed off non-validated conclusions as science. No, it has not been established that every person’s fingerprints are unique.  Oregon found Brandon Myfield was misidentified as the Madrid train bomber.  No, it is not true that hairs can be accurately compared microscopically.  The use of mitochondrial DNA established that such comparisons were demonstrably wrong. As a result we are now engaging in a searching review to find all the cases infected with such inaccurate evidence and determining if the convictions are invalid as a result. There are cases pending today where this is a problem. The Strickland case is an example. In that case, hair comparison report stated that a pubic hair found on the surviving rape and shooting victim, was similar and dissimilar to the other victim. The only thing similar about the pubic hair is that it was human hair. It was different in color and in length, and it turns out that mitochondrial dna testing established that the hair belong to someone other than the defendant that the state tried; my client.  It belong to their first suspect, Dylan Spellman, regarding whom the state’s agent said “we plan to go in another direction” when the DPS lab informed them, it could be tested for DNA at a North Texas forensic lab.  My innocent client was that “other direction.”

The costs of such errors are too high to tolerate them. But gatekeeping courts can spot such sloppy scientific evidence handling and reject it.  In 2017 an additional review of the forensic sciences in criminal cases was published remarking that unvalidated forensic science is the second greatest contributor to wrongful convictions.  The report:  Forensic Science Reform:  Protecting the Innocent is a must read for trial and appellate judges, prosecutors, and defense counsel.  Noting the execution of a person in Texas based on junk and debunked composition bullet lead analysis the report reminds us all “The dead cannot cry out for justice; it is the duty of the living to do so for them.  Lois McMaster Bujold.”

The courts must not accept such mediocrity as a substitute for proof beyond a reasonable doubt. The courtroom must insist upon rigorous science. The poor state of forensic science chronicled in the NAS Committee Report is a testament to this fact.  Discredited bullet lead analysis, microscopic hair comparison, arson misinterpretation of fire artifacts, shaken baby syndrome, bite mark evidence, faulty firearms identification, faulty DNA lab procedures producing dubious results, blood patterns, and crime scene reconstruction should be rejected in Courts.


Daubert sets out non-exclusive factors which trial courts should consider to determine whether the expert is proposing to testify to scientific knowledge that will assist the trier of fact to understand or determine a fact in issue. Thus, the court must assess whether the reasoning or methodology properly can be applied to the facts in issue by asking whether it can be (and has been tested …)

… whether the theory or technique has been subjected to peer review and publication and the court ordinarily should consider the known or potential rate or error…  Finally, general acceptance can yet have a bearing on the inquiry.  Daubert v. Merrell Dow Pharmaceuticals, Inc., 125 L.Ed.2d 469, 482-484 (1993).

The factors outlined are not exclusive and may be employed by a trial court deciding the admissibility of opinion testimony regarding technical or other specialized matter.

“The test of reliability is flexible and Daubert’s list of specific factors neither necessarily nor exclusively applies to all experts or in every case. Rather, the law grants a district court the same broad latitude when it decides how to determine reliability as it enjoys in respect to its ultimate reliability determination. See General Electric Co. v. Joiner, 552 U.S. 136, 143, 118 S.Ct. 512, 139 L.Ed.2d 508 (1997) . . . at the same time . . . Some of Daubert’s questions can help to evaluate the reliability even of experience- based testimony.” Kumho Tire Company v. Carmichael, 119 S.Ct. 1167, 1171, 1176 (1999).

But three Supreme Court Justices suggested in Kumho Tire that the failure to apply one or another of the Daubert factors could be unreasonable and, thus, constitute an abuse of discretion, allowing for reversal of the trial court’s determination upon appeal. Therefore, expert opinion testimony concerning such non-scientific matters such as future dangerousness are subject to the same scrutiny under Daubert as is hard scientific evidence.


After determining if the proffered expert testimony is reliable and, thus, probative and relevant, the trial court must then determine whether, on balance, that testimony might nevertheless be unhelpful to the trier of fact for other reasons. Even reliable and relevant expert testimony might prove unhelpful if it is cumulative, would confuse or mislead the jury or would consume an inordinate amount of trial time. Most importantly, the testimony must constitute knowledge not subjective belief or unsupported speculation. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). Thus, if the court determines that the expert evidence is reliable and relevant, it still must decide whether the probative value of the testimony is outweighed by one or more of the factors identified in Rule 403.

This second step is that contained in Rules 402 and 403 of the Rules of Evidence and is incorporated in Rule 702. The Rule expressly limits opinion testimony. The testimony must be about technical, scientific or specialized matter. It must assist the trier of fact to understand the evidence or determine a fact in issue.

“If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education may testify thereto in the form of an opinion or otherwise.” Texas Rule of Evidence, Rule 702.


Additional rules, case law, subpoena power, and the public information act may render specific items discoverable as a matter of law. The Michael Morton Act states:

“(b)   On a party’s request made not later than the 30th day before the date that jury selection in the trial is scheduled to begin or, in a trial without a jury, the presentation of evidence is scheduled to begin, the party receiving the request shall disclose to the requesting party the name and address of each person the disclosing party may use at trial to present evidence under Rules 702, 703, and 705, Texas Rules of Evidence.  Except as otherwise provided by this subsection, the disclosure must be made in writing in hard copy form or by electronic means not later than the 20th day before the date that jury selection in the trial is scheduled to begin or, in a trial without a jury, the presentation of evidence is scheduled to begin.  On motion of a party and on notice to the other parties, the court may order an earlier time at which one or more of the other parties must make the disclosure to the requesting party.” Art. 39.14(b) of the Texas Code of Criminal Procedure.

Therefore, counsel should enlist formal and informal means to discover information necessary to defend against scientific or other expert opinion-based evidence. For example, in Texas autopsy reports are public documents which may be obtained directly from the medical examiner.

“Records Sec. 11. The medical examiner shall keep full and complete records properly indexed, giving the name if known of every person whose death is investigated, the place where the body was found, the date, the cause and manner of death, and shall issue a death certificate. The full report and detailed findings of the autopsy, if any, shall be a part of the record. Copies of all records shall promptly be delivered to the proper district, county, or criminal district attorney in any case where further investigation is advisable. The records may not be withheld, except that a photograph or x-ray of a body taken during an autopsy is excepted from required public disclosure in accordance with Chapter 552, Government Code, but is subject to disclosure:

  • under a subpoena or authority of other law; or
  • if the photograph or x-ray is of the body of a person who died while in the custody of law enforcement.”, Art. 25, Section 11 of the Texas Code of Criminal Procedure.

Also, case law establishes that the defendant is entitled to production and independent testing of evidence that is material to the defense or the prosecution’s case.  Hinton v. Alabama, 571 U.S. 263, 134 S.Ct. 1081 (2014)[firearm tool mark examination]; U.S. v. Noel, 708 F. Supp. 177 (W.D. Tenn. 1989)[drugs]; U.S. v. Taylor, 25 F.R.D. 225, 227 (E.D.N.Y. 1960)[analysis of drugs]; U.S. v. Dean, 59 F.3d 1479 (5th   Cir. 1995)[crack];  Detmering v. State, 481 S.W.2d 863 (Tex.Cr.App. 1972)[analysis of drugs]; Terrell v. State, 521 S.W.2d 618 (Tex.Cr.App. 1975)[analysis of alleged marijuana]; Wills v. State, 501 S.W.2d 925 (Tex.Cr.App. 1973)[fingerprints], superseded by statute on other grounds, Marysh v. State, 777 SW.2d 44 (Tx. Cr. App. 1909) and Peters v. State, 31 SW.3d 704 (Tex. App. – Houston [1st Dist.] 2000)[concerning admission of unadjudicated other crimes evidence at sentencing hearing]; Ball v. State, 631 S.W.2d 809 (App. 11 Dist.  1982  review  refused)[photographs];  U.S.  v.  Streich,  759  F.2d  579  (7th Cir.)[firearm], cert. denied, 474 U.S. 860 (1985); Sims v. Livesay, 970 F.2d 1575 (6th Cir. 1992)[gun and quilt]; Quinones v. State, 592 S.W.2d 933, 940 (Tex.Cr.App.), cert. denied, 449 U.S. 893, 101 S.Ct. 256, 66 L.Ed.2d 121(1980)[tape recordings]; Whitechurch v. State, 650 S.W.2d 422 (Tex.Cr.App. 1983)[medical records]; Madsen v. Dormire, 137 F.3d 602 (8th Cir. 1998)[serology]. The defendant is also entitled to evidence in the sole possession of the prosecution that is material to the defense.

A defendant is also constitutionally entitled to evidence which impeaches the State’s case or is otherwise favorable to the defendant. See Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1973). The

determination whether some evidence is favorable or impeaching is examined cumulatively and not on an item by item basis. Such evidence must be produced by the prosecution whether or not the lawyer is in possession of it, whether or not the prosecution is aware of it and whether or not it is requested by the defense. Thus, prosecutors need to make inquiries and seek out the favorable information.  The test for production is not a materiality test. Watkins v. State, 619 S.W.3d 265,2 290 (Tex. Crim. App. 2021)[ citing Cynthia E. Hujar Orr & Robert G. Rodery, The Michael Morton Act: Minimizing Prosecutorial Misconduct , 46 St. Mary’s L.J. 407, 414 (2015) at note 121Certainly, the prosecution is in no position to determine what is or is not material to the defense because there is no reciprocal discovery in Texas.  So, prosecutors should provide any information that is unfavorable to its case.  See Kyles v. Whitley, 514 U.S. 419, 131 L.Ed.2d 490, 115 S.Ct. 1555 (1995).

In Kyles v. Whitley, 115 S.Ct. 1555 (1995) the Supreme Court found that the following minor items, considered cumulatively, constituted Brady evidence which should have been produced to the defense. The police uncritically accepted the informant’s version of events even though it contained inconsistencies. The lead detective was either less than candid or less than fully informed. The informant’s behavior raised suspicions that he may have planted evidence where it was found. One out of four eyewitnesses gave a description of the perpetrator that did not match the defendant, but did match the informant. And one eyewitness was coached to state that he observed more than he had.

Thus, any favorable or impeaching evidence regarding forensic science should be provided to the defense regardless of whether the prosecution estimates it is material. When I am describing Brady evidence, I like to tell the story about a phone call I received from a wonderfully professional prosecutor in San Antonio, I got a call from Assistant U.S. Attorney Charlie Strauss. He said, “Cynthia, I hate to tell you this…” and then he went on to tell me about some favorable evidence he had just learned. If the prosecutor “hates to tell you something,” then it is Brady evidence.

Former U.S. Deputy Attorney General, Mr. Ogden, released three memoranda seeking to create a culture of disclosure in the federal system. On January 4, 2010, the DOJ released the memos Guiding Prosecutors to establish a methodical approach to the consideration of discovery obligations that will avoid lapses, that provide a discovery coordinator, provide training to Assistant U.S. Attorney’s and law enforcement, and requiring local U.S. Attorney’s offices to develop discovery policies by year 2010.

At least three additional reasons suggest that a trial court should order pretrial disclosure of expert witness testimony. 1) Expert witnesses are not likely to be swayed from their positions by pretrial disclosure. 2) The trial court must decide admissibility of expert opinion testimony before it is admitted to a jury. 3) Early distillation of the issues upon which expert opinions will have a bearing will promote the orderly conduct of trial.

In fact, because courts may be unnecessarily inconvenienced by lengthy Daubert hearings, counsel should suggest liberal use of criminal depositions to assist the courts in performing their gatekeeping functions before trial.    See

U.S. v. Katz, 178 F.3d 368 (5th Cir. 1999). See Article 39.02, Texas Code of Criminal Procedure (depositions in criminal cases); Rule 15, Fed.R.Crim. P. (depositions). This should constitute a good reason or an exceptional circumstance    for    the    court    to    order    the    deposition    of    an expert

witnesses. During such a deposition one may ask questions about any non- privileged matter relevant to the case. Article 39.02, Texas Code of Criminal Procedure.

“Depositions of witnesses may be taken by either the state or the defendant.  When a party desires to take the deposition of a witness, the party shall file with the Clerk of the Court in which the case is pending an affidavit stating the facts necessary to constitute a good reason for taking the witness’ deposition and an application to take the deposition.  On the filing of the affidavit and application, and after notice to the opposing party, the court shall hear the application and determine if good reason exists for taking the deposition.  The court shall base its determination and shall grant or deny the application on the facts made known at the hearing.  This provision is limited to the purposes stated in Article 39.01.” Article 39.02, Texas Code of Criminal Procedure.

When counsel cannot obtain information through formal means, letter writing and inquisitive telephone calls may net the information. What can counsel do to spot bad science? Use common sense, do their homework, make friends in the scientific community, use the internet and computer based research tools and rely upon each other.

What can the Courts do?  Hire a court’s expert.  Have a special master conduct the Daubert/Kelly hearing and allow criminal depositions to assist the performance of a thorough gatekeeping function.

Stare decisis

One idea courts employ to admit scientific evidence is based on stare decisis. Here, courts admit forensic evidence because it has been allowed in

Evidence previously. But the forensic evidence should be excluded if there has been a misapplication of the methodology.

The idea of using stare decisis is completely contrary to science. Science is always evolving and forward looking. New information is constantly gathered on scientific inquiries. The prime example everyone knows is that prevailing thought once was that the world is flat. Now, we know that is not the case. Stare decisis is a backward-looking function that accepts conclusions or theories because they have been accepted before. However, that does not give room to test its current validity. In one case study, recently presented by judges at a forensic science summit for the courts, the underlying basis for admitting a particular type of evidence was listed as a prior case. Examination of that case revealed that it relied also on an earlier decision. At bottom, it turned out that when the judge looked at the initial case it relied upon to validate the science, that no Daubert analysis or hearing had been performed there either. The practice of relying upon prior decisions, instead of conducting a rigorous case by case determination, produces a house of cards upon which no conviction should stand.

Further Education is Newly Found Evidence

The Court of Criminal Appeals found that an expert’s changed opinion due to further education can constitute newly discovered evidence. In Ex parte Robbins, the jury found the defendant guilty of capital murder for the death of a child by asphyxiation. Ex parte Robbins, 478 S.W.3d 678 (Tex. Crim. App. 2016). During trial, the State’s medical expert testified that the cause of death “was asphyxia due to the compression of the chest and abdomen and that the manner of death was homicide.”  However, the State’s medical expert changed her opinion after re-examining the body nearly 20 years later. The newly discovered evidence was not due to oversight during the autopsy by the expert, it was from progressed knowledge accrued by the expert. The new opinion changed because “[g]iven [her] review of the all the material from the case file and having had more experience in the field of forensic pathology,” the opinion changed to one that the death is undetermined. This was newly found evidence.

This case has been codified into a new type of innocence writ for which the evidence need only meet a preponderance standard.  See Article 11.073, Tex. Code of Crim. Proc.


“The various positions on statutory interpretation seem to agree that the legislative history indicates that the intent of this statute is to provide relief to those who were convicted on science or scientific methodology that is now known to be unsound.” Ex parte Robbins, 478 S.W.3d 678, 692 (Tex. Crim. App. 2016)


It points out that we must pay now, or pay later. Either we must perform the rigorous case by case forward looking determination for the admission of scientific evidence, insist that it has been properly performed in each case reviewed on appeal; or establish meaningful and available remedies when the witnesses are behind the curve and provide flawed testimony.



Fingerprint examiners will compare a latent print to a known print and declare a “match” in their testimony.

We know from the Madrid bombing (in which three FBI fingerprint examiners made the same mistake), two things about fingerprint comparisons. The examination is subjective and, thus, the examiner is influenced by law enforcement bias or theory of the case.  We also know that the fingerprints are not matched- they are compared to determine whether the latent can be excluded. In the Madrid case, the prints had points of comparison, but also points that excluded the latents as a match to the Muslim lawyer from Oregon. And we now know that no fundamental testing has established that everyone’s fingerprints are unique. Just as with DNA testing, an analysis of the probabilities that another person may share the same fingerprint characteristics needs to be done to validate the scientific premise. No longer should counsel allow a witness to offer this presumption that all prints are unique, since no proof backs it up. The question one should ask is whether there is enough detail in the latent print to declare a match to the exclusion of all others?  There is not enough data to answer this question.  Can the details that do not match be explained? About the ACE-V method of fingerprint comparison, the NAS Committee report provides at page 142:

“Ace-V “is not specific enough to qualify as a validated method for this type of analysis. ACE-V does not guard against bias; is too broad to ensure repeatability and transparency; does not guarantee that two analysts following it will obtain the same results…merely following the steps of ACE-V does not imply one is proceeding in a scientific manner or producing reliable results.” p.142


The theory is that different weapons’ inner-works are fashioned by tools that leave a distinct pattern inside the barrel of each weapon. Also, upon firing, each weapon leaves these distinct marks on the ammunition used  in  the  firing. However, studies do not support that the toolmarks left by different tools are all that unique. Page 155 of the NAS Committee report provides about toolmark examination:

“Although some studies have been performed on the degree of similarity that can be found between marks made by an individual tool, the scientific knowledge base for toolmark and firearms analysis is fairly limited.” p. 155

A particular projectile can have the same markings left by similar weapons.  Unless all similar weapons are excluded, one cannot declare a “match” with credibility.


In Texas, hair comparison led to the imposition of the death penalty on Michael Blair, who through later DNA testing was shown to be innocent of the crime. Defense lawyers need to know that microscopic hair comparison has

been found to be demonstrably wrong through Mitochondria DNA testing over 50% of the time. In addition, there are no accepted statistics regarding the frequency of distribution of any particular hair characteristics and no uniform standards for the number of features that appear in hairs compared before an examiner may declare a match. Thus, microscopic hair comparisons are without value and should not be admitted in evidence. Page 161 of the NAS Committee report states:

“The committee found no scientific support for the use of hair comparison for individualization in  the  absence  of  nuclear DNA. Microscopy and MtDNA analysis can be used in tandem and add to one another’s value for classifying a common source, but no studies have been performed to specifically quantify the reliability of their joint use.” p. 161


While there may be some value in handwriting comparisons, the NAS Committee found that their scientific basis needed strengthening:

“The scientific basis for handwriting comparisons needs to be strengthened… Although there has been only limited research to quantify the reliability and replicability of the practices used by trained document examiners, the committee agrees that there may be some value in handwriting analysis.” NAS Committee report at p. 167.


For too long local firemen and law enforcement have relied on wives’ tales to conclude that fires have been set by arson. Texas Monthly, a statewide magazine recently wrote an article about poor forensic science entitled “Weird Science”, Michael Hall (May 2010 Issue) []. The article notes that:

“Testimony from forensic experts can be the most persuasive evidence presented at trial, but often juries don’t realize that the analysis of hair, fire, and even fingerprints may not be so scientific. And as the story of deputy Keith Pikett, master of the dog-scent lineup, shows, investigations can sometimes lead to the greatest crime of all: putting innocent people behind bars.”

I commend the article to you not only for its spot-on exposure of bad forensic science used in courts, but also for its simplified layman’s explanation of why and how the science is flawed. Use the article to help you articulate the fundamental wrongness of much that passes for science. Use it to conduct a searching exam of science you will allow in court.  The magazine also covers the Todd Willingham case, a case where a man was wrongly executed in Texas by the use of old wives’ tales in an arson investigation.

“Willingham had been convicted of murdering his three children by setting fire to his family’s Corsicana home in 1991, and he had been executed in 2004. The guilty verdict came primarily because of the testimony of two longtime arson investigators—an assistant fire chief and a deputy fire marshal—neither of whom had much education in the actual science of fire. The two men sleuthed their way through the burned-out structure, and though they found no indisputable physical evidence of arson in the house—no gas can, no kerosene, no matches—they did find, on the floor of the children’s bedroom, strange marks that they identified as ‘pour patterns,’ which indicated that an accelerant had been used. They also found ‘crazed glass,’ pieces of broken window suffused with spiderweb cracks, which suggested that an accelerant had been used, causing the fire to burn superfast and superhot. And they found charring under a threshold plate; common sense indicated that an accelerant had been poured there too. By the time their tour was complete, they believed the fire had been intentionally set.

Willingham protested his innocence until his execution.

Afterward, others began protesting too, including seven contemporary arson scientists and investigators, some of whom had done actual science experiments and analytical chemistry on fires and all of whom were stunned at the lack of hard science used to determine that the fire was arson. Each of the seven reached the conclusion that every indicator of arson the two original investigators had found was invalid. ‘The investigators had poor understandings of fire science and failed to acknowledge or apply the contemporaneous understanding of the limitations of fire indicators,’ wrote Craig Beyler, a nationally recognized fire scientist, in an August 2009 report to the state’s new Forensic Science Commission, a panel founded by the Legislature to investigate faulty or negligent forensic science. ‘Their methodologies did not comport with the scientific method or the process of elimination. A finding of arson could not be sustained.’” Texas Monthly, “Weird Science”, Michael Hall (March 2010 Issue).

The NAS Committee Report acknowledges  the  problem  is  widespread. At page 173 it states:

“The scientific foundations exist to support the analysis of explosions, because such analysis is based primarily on well- established chemistry…By contrast much more research is needed on the natural variability of burn patterns and damage characteristics and how they are affected by presence of various accelerants. Despite the paucity of research, some arson investigators continue to make determinations about whether or not a particular fire was set…Experiments should be designed to put arson investigation on a more solid scientific footing.” Id. at p. 173.

The crazed glass was not indicative of a hot fire, but was the result of water used to put out the fire hitting the hot glass.  The pattern on the floor was not an indicator that accelerants were used, it indicates where the fire was getting fuel from the oxygen coming in the windows of the home.  And no accelerants were present where the fire had burned.  The fire was an accident.


Bloodstain pattern analysis has value as long as care is taken to conduct experiments under identical circumstances to determine the results on bloodstain patterns of any certain action. Because the same pattern can result from any number of actions and variables, extreme care should be taken with such evidence. During a recent training put on by the NACDL, the Innocence Project and DOJ, I observed a slow motion film of a close range gunshot. The cloud of gases emanating from the gun caused a blowback of blood vapor and spray that left one with the wrong impression about what had occurred if you did not see the experiment. Neither the position of the gun nor the gases from the gun fire are visible factors at the scene. In order to be aware of all the variables in bloodstain pattern analysis, there is no substitute for reconstruction of the actions in a carefully crafted experiment. The NAS Committee Report states about bloodstain pattern analysis at page 179:

“‘Scientific studies support some aspects of blood pattern analysis’,’ However, ‘many experiments must be conducted to determine what characteristics of bloodstain pattern are caused by particular actions during a crime and to inform the interpretation of those causal links and their variabilities.’” Id. at p. 179.

“Extra care must be given to the way in which the analysis are presented in court. The uncertainties associated with bloodstain pattern analysis are enormous.” Id. at p. 179


While mass gas spectrometry is a sound basis to analyze chemical content of a controlled substance, sources of error and the quality of the result are not typically revealed in the opinion testimony relaying the results. A good example is an intoxicated manslaughter case I handled on the motion for new trial and appeal. The decedent was stopped partially in the dark roadway at 3 a.m. in a perfectly functional car. She had seven crack pipes in her purse and her eyes were already rolled back in her head immediately after the accident with my client. An EMIT test of her blood taken a few days later showed cocaine and methamphetamine. A mass gas chromatography (“GC”) test produced by the Department of Public Safety was said to be “negative” and “without a trace of analytes.”

It turns out that the blood sample did not contain the proper preservative, the test was not done for a year, cocaine degrades substantially over time, and there was sufficient trace of cocaine analytes to establish that the decedent had cocaine onboard at the time of the accident. Coupled with the medical testimony and her parking partway in the roadway with a fully functional car proved that she probably died of a heart attack caused by a drug overdose before the traffic accident.

In a case out of Dallas, Texas, the lab tech was using the same GC test result strip over and over again in every case. It turns out that she was ingesting the cocaine she was supposed to test. That is another, but not recommended, or proper way to test for cocaine. In yet another, GC case out of New Mexico, the results reported only a 47% certainty that the substance was as suspected. This is not good enough proof to meet the beyond a reasonable doubt standard. The NAS Committee Report warns about getting enough information to determine whether the test results are erroneous, misleading or obscured. At page 135 it states:

“While the ‘chemical foundations for the analysis of controlled substance are scientifically sound,’ ‘possible sources of error are not commonly included’ and the ‘style of reporting is often inadequate because it may not provide enough detail to enable peer review or other courtroom participants…question the sampling scheme, processes of analysis, or interpretation.’” Id. at p. 135


Applying dentistry to criminal law may work when one is attempting to identify remains. But bite mark comparison is of questionable value. It is one thing to collect DNA from swabs of the skin to identify the biter. But using photography or overlays to identify a bite mark pattern is controversial because bite marks on the skin will change over time. They are also distorted by the elasticity of the skin, the unevenness of the surface bite, and swelling and healing. At page 174 of the NAS Committee Report, it confirms that:

“These features may severely limit the validity of forensic odontology. Also, some practical difficulties, such as distortions in photographs and changes over time in the dentition of suspects, may limit the accuracy of the results.”

“The guidelines of the ABFO for the analysis of bite marks list a large number of methods for analysis, including transillumination of tissue, computer enhancement and/or digitalization of the bite mark or teeth, stereomicroscopy, scanning electron microscopy, video superimposition, and histology. The guidelines, however, do not indicate the criteria necessary for using each method to determine whether the bite mark can be related to a person’s dentition and with what degree of probability. There is no science on the reproducibility of the different methods of analysis that lead to conclusions about the probability of a match. This includes reproducibility between experts and with the same expert over time. Even when using the guidelines, different experts provide widely differing results and a high percentage of false positive matches of bite marks using controlled comparison studies.” Id. at p. 174.


Most other commercial industries and scientific communities avoid using CSLI without other location technologies because it is unreliable in practice and unsound in technique. In fact, data released by the Federal Communication Commission (“FCC”) in 2013 showed that more than two-thirds of the calls to 9-1-1 do not meet the four requirements defined in Rule 702. First, the testimony is not based upon sufficient facts or data. There is no factual basis for drawing pie shapes on a map, and the cellular company does not provide such data to experts in cases. The physical location of the cell towers not factually confirmed because cellular carriers maintain the geo-location coordinates of cell towers and provide those locations to an expert for use in his plotting of the locations of the towers.  Building and locating the towers is performed by third parties. And so the actual location of a tower may be different than its listed location.  In addition,  no data regarding the actual coverage area of any tower at the time of an incident is not provided by the cellular carrier, and there is no method that can be used to determine the coverage of a cell tower at the time of an incident based on historical call detail records. It is not even accurate location information necessary to find a caller in crisis, because in most cases the 9-1-1 call center received data showing only the location of a cell tower from which connection the call originated. Such “information [is] of little use to emergency responders given the large area covered by each tower.”

The only accurate way to determine an individual’s location is through the use of a Global Positioning System (“GPS”). Unlike cellular phones, GPS operates using satellites. Accordingly, so that emergency responders can accurately locate a caller in distress, the FCC revised its regulations to require cell phones to contain GPS chips as part of an E911 initiative. If the  CSLI  methodology  was at all accurate, there would be no  need for the  FCC to  require  GPS chips in phones. A methodology that has been determined by independent government agencies as not reliable on which to stake a caller’s life should not be accepted as reliable enough to risk a defendant’s liberty.

It is well-settled black letter law that courts may exclude from the jury, expert testimony based on theories that have not gained acceptance within the scientific community. See Charles Alan Wright et al., 29 FEDERAL PRACTICE & PROCEDURE—EVIDENCE §§ 6266(1st ed.)(“[J]udicial interference with the jury’s power to weigh [expert] evidence may be warranted where expert testimony is based on emerging scientific theories that have not gained widespread acceptance within the scientific community.”).

The Supreme Court in Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 593–94 (1993) has held that “submission to the scrutiny of the scientific community is a component of ‘good science,’ in part because it increases the likelihood that substantive flaws in methodology will be detected.”

Also using a pie-slice- shaped “Sectorized-Directional” symbol is not illustrative of a minimum or maximum coverage area of the cell tower and sector, but rather demonstrates the direction the sector’s antennae on the cell towers are oriented. It also not illustrative of a minimum or maximum coverage area and that no part of the “Sectorized-Directional” symbol is to scale. In fact, neither the shaded areas nor the sector arms can scientifically or technically represent the minimum or maximum coverage area. These figures are made at the witness’ discretion and are not a true indication of any coverage of a cell tower.

At any point in time, a cell phone may “see” up to seven towers and can pick any of those seven towers to connect a call. See Matthew Tart, Iain Brodie, Nicholas Gleed, James Matthews, Historic cell site analysis– Overview of principles and survey methodologies, Journal of Digital Investigations, Volume 8 (185-193), October 2012. The actual determination of which cell tower is used is complex and hinges on a multitude of factors that are not memorialized in the call detail records.

For example, a cell site may become congested because of a high rate of traffic. In order to reduce congestion on a cell site, a phone may select another cell site that does not necessarily have the strongest signal. The effects of “clutter,” either by line of sight or localized interference, will mean there may be marked differences of signal strength. Radio signal interference from current weather conditions, known as “attenuation,” can cause fade of the signal. The condition, make, and model of the particular cell phone being used will impact the strength of the signal, as well as the amount of interference in the area from other towers. Natural and man-made clutter in the area such as trees, hills, buildings, bodies of water, and signs cause radio waves to be either reflected, refracted, or absorbed, also referred to as Rayleigh fading, will impact signal strength.

Opinions about location based upon CSLI do not meet the four requirements defined in Rule 702. First, the testimony is not based upon sufficient facts or data. There is no factual basis for drawing pie shapes on a map, and the cellular company does not provide such data to experts in cases. The physical location of the cell towers is factually unsupported because cellular carriers maintain the geo-location coordinates of cell towers and provide those locations to an expert for use in his plotting of the locations of the towers; however, data regarding the actual coverage area of any tower at the time of the incident is not provided by the cellular carrier, and there is no method that can be used to determine the coverage of a cell tower at the time of an incident based on historical call detail records. It is simply not possible to reliably determine the coverage area of a cell tower antenna as it relates to a particular cell phone at the time of call.

These are just a few areas of forensic evidence used in criminal cases and the problems they present.  Only thorough conduct of Daubert/Kelly hearings whenever scientific and expert evidence is involved will serve Courts’ gatekeeper functions and help ensure proper outcomes to the extent that we can do so.

[1] A great deal of data, study and analysis supports DNA evidence – there is no other area of forensic science that is validated.

[2] The Court must also determine if the expert is qualified to provide the opinion and whether the opinion is helpful to the jury.  In addition, the Court should acknowledge an expert opinion can be found concerning any issue. However, not all matters require an expert opinion to assist the jury in making a determination.

[3] A scientist may be unqualified because he has not kept up-to-date with the science or because she was never knowledgeable about it in the first place.  Or a scientist may be unqualified to render an opinion in a case because they are not adequately informed of all the relevant scientific facts.

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