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July 2013 , Page 16 

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The Hair Microscopy Review Project: An Historic Breakthrough For Law Enforcement and A Daunting Challenge For the Defense Bar

By Norman L. Reimer

NACDL staff members are working with the Innocence Project and the FBI to review thousands of cases in which the use of microscopic hair comparison evidence may have resulted in wrongful convictions. NACDL needs all defense lawyers in the United States to aid in this effort to identify cases — regardless of whether the FBI was involved.

If you have knowledge of this evidence being used in a case, or would like to assist on this important project, contact NACDL Resource Counsel Vanessa Antoun at vantoun@nacdl.org or 202-465-7663.  

NACDL’s recently announced partnership with the Innocence Project (IP) and the Federal Bureau of Investigation (FBI), once an almost inconceivable concept, embodies an historic breakthrough in how law enforcement addresses overstated scientific conclusions or opinions, but also presents an extraordinary challenge for the legal profession.1 The existence of the Hair Microscopy Review Project constitutes a commendable recognition by the FBI and the Department of Justice (DOJ) that there is an affirmative duty to correct when events establish that the evidentiary value of a scientific opinion has exceeded the limits of science. At the same time, the criminal defense bar has an overarching obligation to ensure that individuals who may have been wrongfully convicted have access to qualified counsel to pursue all available relief. This article will explain the contours of the project, the protocols that will be applied in the collaborative review process, and the nature and extent of the notification of error. Finally, it will describe the challenges that await clients and lawyers after the error has been disclosed.

The Contours of the Project

In July 2013, NACDL and the IP signed the groundbreaking and historic agreement with the FBI and DOJ to review thousands of criminal cases in which the FBI conducted microscopic hair analysis of crime scene evidence. Two major developments created the impetus for this review. First, in 2009, the National Academy of Sciences (NAS) issued its report on forensic science and specifically identified microscopic hair comparison evidence as problematic.2 The report observed that “[n]o scientifically accepted statistics exist about the frequency with which particular characteristics of hair are distributed in the population. There appear to be no uniform standards on the number of features on which hairs must agree before an examiner may declare a ‘match.’”3 Further, the NAS committee found “no scientific support for the use of hair comparisons for individualization in the absence of nuclear DNA. Microscopy and mtDNA analysis can be used in tandem and may add to one another’s value for classifying a common source, but no studies have been performed specifically to quantify the reliability of their joint use.”4 

The second and more direct triggering event was the exoneration of three men between 2009 and 2012 who had served lengthy prison sentences, and whose convictions were tainted by microscopic hair comparison evidence that exceeded the limits of science. DNA testing contradicted the conclusions of three different FBI hair examiners who had provided the flawed testimony.5  

The review will focus on cases in which either the FBI laboratory reports or the testimony included statements that exceeded the limits of science. NACDL and the IP began preliminary discussions with the FBI in the spring of 2012, and in July 2012 the DOJ confirmed the launch of the largest postconviction review ever conducted by the FBI.6 Since that time, NACDL and the IP have worked together with the FBI to establish protocols for the project and the content of the eventual notifications.7 

It is important to understand the breadth of the universe of cases that will be subject to review. The review will focus on all cases analyzed prior to Dec. 31, 1999, and will extend back at least until the early 1980s or earlier if cases can be identified. The reason cases in which the offense occurred after 2000 will not be examined is that beginning in 1996, DNA testing augmented hair microscopy as the means of determining whether two hair specimens were determined to be a match. Hence, at least in terms of the FBI laboratory, the practice of relying solely upon hair microscopy ended. Because the FBI provided microscopic hair analysis for state and local law enforcement entities, many, if not most, of the cases will be state prosecutions.8 

The touchstone for the review is a fundamental agreement as to the permissible limits of the science of hair microscopy. NACDL and the IP have agreed with the FBI that an examiner’s testimony concerning the relationship between two hairs is appropriate if it reflected the fact that hair comparison could not be used to make a positive identification. Instead, it could indicate, at the broad class level, that a contributor of a known sample could be included in a pool of people of unknown size, as a possible source of the hair evidence (without in any way giving probabilities, as an opinion to the likelihood or rareness of the positive association, or the size of the class) or that the contributor of a known sample could be excluded as a possible source of the hair evidence based on the known sample provided.9 In essence, with some specific exceptions in cases involving dyed hair or hair evincing signs of certain diseases, hair microscopy can reliably exclude a match but it cannot support any statement as to the likelihood of a match.10  

Types of Error

When the testimony concerning hair microscopy is examined through the lens of this basic understanding about the limits of the science, three types of error can be identified:

Error Type 1

The examiner stated or implied that the evidentiary hair could be associated with a specific individual to the exclusion of all others.


A: I found brown, Caucasian head hairs on two items of clothing, the sports coat, and a pair of slacks that were reported to me as belonging to [the defendant]. Now, these hairs matched in every observable microscopic characteristic to that known hair sample of DEC [the decedent] and consistent with having originated from her. In my opinion, based on my experience in the laboratory and having done 16,000 hair examinations, my opinion is that those hairs came from DEC.

Error Type 2

The examiner assigned to the positive association a statistical weight or probability or provided a likelihood that the questioned hair originated from a particular source, or an opinion as to the likelihood or rareness of the positive association that could lead the jury to believe that valid statistical weight can be assigned to a microscopic hair association.


Q: Now, based on your training and experience and your expertise in the field, and based on your knowledge of hair transfer and hair comparison, and based on the work done in this case, do you have an opinion, within the degree of scientific certainty, as to whether or not the pubic hair found in the underpants of [victim] came from [defendant]?

A: I would say that it would be a very high degree of probability that it does. Or to reverse it, I would say the chances of it being from somebody else, other than Mr. XX, would be highly unlikely at best.

Error Type 3

The examiner cites the number of cases or hair analyses worked in the lab and the number of samples from different individuals that could not be distinguished from one another as a predictive value to bolster the conclusion that a hair belongs to a specific individual.


A: Now over the last 12 years, I personally have looked at hairs from about 10,000 different people, and over that time, I’ve only had two occasions out of the 10,000 people where I had hairs from two different people that I could not separate them.

The Review Process and Protocols

As of early August, the FBI has identified approximately 21,700 cases in which FBI hair examiners may have conducted a microscopic hair comparison. Of the first 15,000 cases reviewed, lab reports finding a positive association between a questioned hair and a suspect’s (or victim’s) hair were discovered in approximately 2,100 cases. Already more than 120 trial transcripts have been reviewed with at least one type of error present in most of them.

In most cases, the FBI will initiate the review through internal processes within the laboratory. After the reports with a positive association have been identified, the FBI will seek additional information from the contributing agency, usually a state or local law enforcement entity, and from the prosecuting authority. NACDL and the IP have also sought information and transcripts, specifically focusing on capital cases. The ultimate goal in all cases in which the report indicates that there was a positive association is to obtain the transcript or otherwise determine whether the evidence was utilized in a manner that exceeded the permissible limit of science.

This is a truly collaborative process, and as a result, if the FBI is unsuccessful in getting information about a case from the contributing agency or from the prosecutor, NACDL and the IP will make independent efforts to get the information necessary to complete a meaningful review.

After the transcript or other relevant information is on hand, the FBI will conduct a review pursuant to the above-described agreement as to the limits of hair microscopy to determine whether or not any of the three types of error are present. After the FBI makes its determination, it will share its findings and the relevant materials with NACDL and IP for an independent review. NACDL and the IP will conduct that review within two weeks, and either agree with the FBI or specify any disagreement. The FBI will then consider any objections to the initial finding, and either modify its conclusions or confer with representatives from NACDL and IP to explain the rationale for their conclusion. At the end of this review process, the DOJ will send letters of notification. Those letters will either indicate that there is agreement as to the types of error, or will provide the FBI finding and note the contrary position of NACDL and the IP.

The Notification of Error

The DOJ will send the notification of the review results to the appropriate prosecutor, and shortly thereafter the notification will be sent to the defense counsel as well as to NACDL and the IP.12 If there is no defense attorney, steps will be taken to notify the defendant. Where error has been found, there will be several key ingredients in the letter of notification.

First, the letter will specify each of the types of error found in the case, with appropriate references to reports or transcripts. The letter will unequivocally state that because the statements by the examiner exceeded the limits of science, they were invalid.13  

Second, the letter will specify that upon request of the prosecutor or court order, the FBI will conduct DNA testing on the hair samples, or, if the hair samples cannot be located, will offer DNA testing for any other biological evidence in the case, provided that the chain of custody has been maintained.14  

Third, in federal cases the DOJ will specifically state that it is waiving any statute of limitations defense or procedural bars under 28 U.S.C. § 2255.15 In state cases, the DOJ will note that it is waiving those procedural obstacles in federal cases.16 

The Challenges Upon Notification

First and foremost, it is imperative to understand what the review process does not include: there will be no determination of materiality whatsoever.17 Accordingly, when either existing or new counsel evaluates the significance of the error notification, the first order of business will be to determine the importance of the microscopic hair evidence under the specific facts and circumstances of the case. For individuals with active cases, especially people under a sentence of death, this may be a manageable chore for existing counsel. But for individuals whose cases were resolved years ago, and for all cases in which new counsel will have to be identified, this could be quite a herculean task.

As the project has been crafted, NACDL and the IP will continue to follow the cases after notification. In cases in which there is an existing attorney, the organizations will take steps to confirm that the lawyer has received the letter and will follow up. In other cases, the project team will endeavor to ensure that the defendant is aware of the notification and ascertain whether the individual seeks representation. In cases in which a person seeks representation, but is unable to secure such representation on his own, NACDL has pledged to seek volunteer attorneys who will be available to assist these clients. NACDL Past President Steve Benjamin stated that “NACDL needs all defense lawyers in the United States to aid in this effort to identify cases in which hair microscopy evidence was used in a conviction, regardless of whether the FBI was involved in the analysis or testimony involved in the conviction.”

As to all cases, irrespective of whether the case is handled by pre-existing counsel or by new counsel, NACDL and the IP will provide resources to support the lawyers. As of the date of this writing, the two organizations are in the process of developing practice guidance memoranda and assembling lawyers to serve as resources and consultants who can be available throughout the various regions of the country to provide postconviction litigation guidance. Albeit highly ambitious, the goal will be to see that every client who may have suffered a wrongful conviction as a result of the use of this flawed evidence has the best possible chance of securing relief on the merits.

What to Do About Flawed State or Local Examinations

There is another class of cases, which might be quite substantial, that is not embraced by the FBI’s historic review: cases in which flawed microscopic hair comparison evidence was presented by state or local examiners. Although many of these examiners may have been trained by the FBI laboratory, the review is limited to cases in which FBI examiners offered statements that exceeded the permissible limits of science. What redress will there be in these cases?

On April 11, 2013, the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB) posted an extraordinary advisory. Noting the FBI review project, ASCLD/LAB essentially called on all laboratories to review their work involving microscopic hair analysis:

It has recently been brought to ASCLD/LAB’s attention that the FBI and the USDOJ are jointly in the process of reviewing pre-1999 microscopic hair comparison cases. … The purpose of this notification is not intended to highlight the events taking place in the FBI laboratory, but to raise awareness within the forensic science community and the criminal justice system that there may be a broader need for review of reports and testimony provided in microscopic hair comparisons made prior to the routine implementation of DNA technology in hair comparisons.

The ASCLD/LAB advisory went on to note that “we have an ethical obligation to ‘take appropriate action if there is potential for, or there has been, a miscarriage of justice due to circumstances that have come to light, incompetent practice, or malpractice.’”

Indeed, NACDL has learned that at least one state forensic science board has taken steps in furtherance of this advice. On July 12, 2013, the Texas Forensic Science Commission took initial steps to commence a review of microscopic hair comparison analysis conducted by laboratories in Texas. It remains to be seen whether other states will undertake a similar review. Even more importantly, it remains to be seen whether and to what extent local prosecutors will follow the model set by the FBI and DOJ and similarly embrace a duty to correct.

Irrespective of how all of this unfolds, NACDL and the IP are determined to develop mechanisms to assist clients and their counsel, regardless of the source of the flawed scientific evidence. In a perfect world, funds would be available to provide every client whose case was tainted by overstated scientific conclusions or opinions with the necessary resources to mount the necessary postconviction challenge. But this is far from a perfect world. And hence, it will be up to the defense bar and the legal profession as a whole to ensure that this wrong is rectified and that fundamental rights are vindicated. This project is not only vital for dealing with the problem of flawed microscopic hair analysis evidence. It could also serve as a model for rectifying flaws that may be identified in other disciplines.


  1. The project is a collaboration among NACDL, the Innocence Project, and the FBI. This partnership is aided by a team of pro bono lawyers from Winston & Strawn LLP, and Michael Bromwich of The Bromwich Group.
  2. National Academy of Sciences, Strengthening Forensic Science in the United States: A Path Forward (2009).
  3. NAS Report, at 160.
  4. NAS Report, at 161.
  5. The cases were those of Donald Gates (2009), Kirk Odom (2012) and Santae Tribble (2012). Keith L. Alexander, DNA Tests Set Free D.C. Man Held in Student’s 1981 Slaying, Wash. Post, Dec. 16, 2009; Spencer S. Hsu, Kirk L. Odom Officially Exonerated; DNA Retesting Cleared Him in D.C. Rape, Robbery, Wash. Post, Jul 13, 2012; Spencer S. Hsu, D.C. Judge Exonerates Santae Tribble in 1978 Murder, Cites Hair Evidence DNA Test Rejected, Wash. Post, Dec. 14, 2012.
  6. Justice Department, FBI to Review Use of Forensic Evidence in Thousands of Cases, Wash. Post, July 10, 2012.
  7. Even while discussions were continued, the review commenced with a focus on any cases in which an individual was under a death sentence with a firm execution date. This early review led to the issuance of a letter in the case of Willie Jerome Manning, which led to an eleventh hour stay. Manning v. State,112 So. 3d 1082 (Miss. 2013) (granting motion to stay execution pending further order of court).
  8. There is an entire other universe of cases that is not part of the joint project with the FBI and DOJ. Many cases in which evidence of microscopic hair comparisons was introduced involved state and local laboratory examiners. Often those laboratory examiners were trained by the FBI, and it is likely that similar defects arose in their lab reports and testimony. Some thoughts about how those cases may be handled are discussed infra at page 18.
  9. This rather lengthy formulation reflects the formal agreement among the FBI, IP, and NACDL as to the permissible limits of microscopic hair analysis.
  10. Indeed, in a highly regarded controlled FBI study of mitochondrial DNA analysis versus microscopic hair comparisons, the fallibility of hair microscopy was confirmed. In 11 percent of cases in which a competent hair examiner declared two hairs to be “similar,” subsequent DNA testing revealed that the hairs did not match. Max Houck & Bruce Budowle, Correlation of Microscopic and Mitochondrial DNA Hair Comparisons, 47 J. Forensic Sci. 964-967 (2002). 
  11. These examples are provided solely to illustrate the three types of error.
  12. The delay was built into the protocol in order afford prosecutors an opportunity to make appropriate victim notifications.
  13. The specific language as to the determination of error will be as follows: “We have determined that the microscopic hair comparison analysis testimony or laboratory report presented in this case included statements that exceeded the limits of science and were, therefore, invalid.”
  14. The specific language as to the offer of testing will be as follows: “In the event that your office determines that further testing is appropriate or necessary, the FBI is available to provide mitochondrial DNA testing of the relevant hair evidence or STR testing of related biological evidence if testing of hair evidence is no longer possible, if (1) the evidence to be tested is in the government’s possession or control, and (2) the chain of custody for the evidence can be established.”
  15. The specific waiver language is as follows: “In the event that the defendant seeks postconviction relief based on the department’s disclosure that microscopic hair comparison laboratory reports or testimony used in this case contained statements that exceeded the limits of science, we provide the following information to make you aware of how we are handling such situations in federal cases. In such cases under 28 U.S.C. § 2255, in the interest of justice, the United States is waiving reliance on the statute of limitations under Section 2255(f) and any procedural-default defense in order to permit the resolution of legal claims arising from the erroneous presentation of microscopic hair examination laboratory reports or testimony.”
  16. Naturally, it would be wonderful if the DOJ could waive those considerable procedural obstacles in state cases. But that is not possible either as a matter of law or as a practical matter due to principles of federalism. In advocating for this language, the representatives of NACDL and the IP hope that the waiver of bars by the DOJ with respect to federal cases will encourage state prosecutors to follow that example.
  17. Specifically, the notification letter will include this proviso: “We take no position regarding the materiality of the error in this case.”
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