November-December 2011

Meeting attacks on forensic science through TDCAA’s Forensic Evidence Project

Be on the lookout for help from the association on countering challenges to forensic science in the courtroom.

John Bradley

District Attorney in Williamson County

In 2009, the National Academy of Sciences (NAS) issued a federal government-mandated report on the status of forensic science in the United States.1 The report has been presented through the media as critical in some respect of nearly every forensic science except DNA testing. To provide Texas prosecutors with accurate and timely research and information to understand and meet these new challenges, the Texas District and County Attorneys Association (TDCAA) has started a Forensic Evidence Project. This article will give prosecutors an introduction to the work of that project and provide an example of the work product that will soon help prosecutors in the courtroom.

    During meetings to update the strategic long-term plan for TDCAA, prosecutors indicated that they need help in dealing with the growing attacks on the use of forensic evidence in the courtroom. Many of the concerns stemmed from specific problems that have developed in Texas crime labs. However, many of the concerns arose from the national attention to the subject created by the issuance of the NAS report and its subsequent media attention. At the invitation of TDCAA, a group of prosecutors2 joined the Forensic Evidence Project and began working on the creation of single-page, two-sided summaries on how to handle forensic science challenges for several specific subjects.

      For example, I was assigned to develop a sheet on the subject of fingerprint comparison. The goal was to summarize the purpose, process, and modern challenges to using an expert witness to provide testimony regarding fingerprint evidence. So, what could be so controversial about a forensic science that has been in use for over 100 years?

    Fingerprint identification is a field of forensic science that uses an expert witness to visually identify the unique characteristics associated with a latent fingerprint left at a crime scene or deliberately placed on a document or in a database. The expert then compares that latent print to a known print obtained from an individual to determine whether the individual was the source of the latent print.

    Each print, whether it comes from the finger, palm, toe, or sole of the foot, contains unique patterns of ridged skin. Those patterns are often transferred to a surface when a finger deposits oil, blood, sweat or ink onto the surface. The pattern can later be collected through photography or various other techniques for collecting a latent print.

    The expert relies on a process called the acronym-named ACE-V method (Analysis, Comparison, Evaluation, and Verification) when conducting the comparison between a latent and known print. This process has been recognized by numerous courts as a reliable method for conducting a fingerprint comparison and coming to a conclusion as to whether a particular individual was the source of a latent print.

    The NAS report included a discussion of fingerprint comparison and identified several issues of concern.3 Subsequently, in several cases throughout the United States, criminal defendants attempted to exclude fingerprint comparison testimony as unreliable by simply referencing the NAS report. However, several courts, after conducting an extensive review of the report and listening to substantial testimony on the subject, have concluded that fingerprint comparison is reliable and admissible.4

    In another high-profile attack on the field of fingerprint comparison, a criminal defendant suggested that an FBI report5 on the misuse of fingerprint evidence in a Madrid bombing case provided support for the exclusion of fingerprint comparison evidence in criminal cases. However, an exhaustive review of that report in a federal court hearing resulted in the conclusion that fingerprint comparison is a reliable and admissible forensic field.6

    Frankly, the field of fingerprint comparison is so well-known and accepted in Texas courts that a trial judge may take judicial notice of the reliability of the field and the ACE-V method for making a comparison.7 Nevertheless, the expert witness still must provide proof that the ACE-V method was properly applied in a particular case before such evidence is ultimately admissible.

    In choosing an expert to conduct a fingerprint comparison and testify in court, Texas prosecutors should be aware that there is no single certifying process for identifying who is a proper expert. Indeed, the field of fingerprint analysis is not subject to the statutory requirement that it be conducted only in an accredited laboratory.8 The prosecutor should make sure, though, that the fingerprint examiner has sufficient training and experience to qualify as an expert.9

    The fingerprint identification community has not specified a uniform number of points of comparison that are necessary to establish a match between a latent and known print. The number is left to the judgment of the experienced examiner and depends on the quality and size of the available prints.10  However, specific standards for reaching a conclusion have been established by the Scientific Working Group on Friction Ridge Analysis, Study, and Technology (SWGFRAST).11

    In conclusion, in December Texas prosecutors will receive six single sheet summaries of forensic fields, helping them address challenges in the courtroom. This is just the beginning for TDCAA. Please send us your suggestions for additional forensic information. We all need to work harder to make sure we present solid forensic evidence during a trial.


1 Any prosecutor may read the report online or purchase the report in hardback, but a free download in PDF format is available at catalog.php?record_id=12589. A shorter executive summary is also available. Every prosecutor should take the time to read the report.
2 The prosecutors included: John Bradley (Williamson County DA, fingerprint analysis), Alan Curry (Harris County Assistant DA, eyewitness identification), Lindsey Roberts (Williamson County Assistant DA, collision reconstruction), Richard Alpert (Tarrant County Assistant DA, blood alcohol testing), Lance Long (Harris County Assistant DA, DNA testing), and Warren Diepraam (Montgomery County Assistant DA, drug toxicology).
3 National Research Council, Strengthening Forensic Science in the United States, A Path Forward, pp. 102-04, 136-45 (2009).
4 Commonwealth v. Gambora, 933 N.E.2d 50 (Mass. 2010); Johnston v. State, 27 So.3d 11 (Fla. 2010); United States v. Rose, 672 Supp. 2d 723 (D. Md. 2009); see also Swirls and Whorls: Litigating Post-Conviction Claims of Fingerprint Misidentification after the NAS Report, 2010 Utah L. Rev. 267 (2010).
5 For a downloadable PDF of the report, go to:
6 United States v. Rose, 672 F.Supp.2d 273 (D. Md. 2009).
7 Hernandez v. State, 116 S.W.3d 26 (Tex. Crim. App. 2003). For an example of such judicial notice, see Moore v. State, 109 S.W.3d 537 (Tex. App.—Tyler 2001).
8 See Tex. Code Crim. Pro. art. 38.35(a)(4)(A); Tex. Admin. Code, Title 37, Part 1, Chapter 28, Rule 28.146(1)(b).
9 Mouton v. State, 892 S.W.2d 234 (Tex. App.—Beaumont 1995, pet. ref’d); Sepeda v. State, 2009 Tex. App. LEXIS 9234 (Tex. App.—Amarillo 2009, pet. ref’d) (not for publication).
10 United States v. Havvard, 117 F.Supp.2d 248 (D. Ind. 2000).
11 For details on those standards, go to