So you have fingerprint evidence against your client. There are several possible lines of attack that you should explore. Depending on your case, you may want to use one or more of them:

1. Do you have a theory of the crime in which a fingerprint match does not necessarily indicate responsibility for the crime? Did your client have “legitimate access” to the surface where the fingerprint was found? Could the fingerprint have been deposited at a time that does not inculpate your client? You don’t need much in the way of resources from this site. Your best resources are your own skills as a defense lawyer. Also beware to opinions as to age of latent, manner of deposition, and so on. See
• Modern Scientific Evidence in the Books folder in support of the point that “absolute determinations” of time of deposition of latent fingerprints “are not generally possible.”
• Starrs, “Scientific Supermen” in the Articles folder for a review of this kind of testimony.
2. Was the fingerprint evidence fabricated or fraudulently attributed to your clients? While this is presumably a rare occurrence, no data is available to indicate how rare, so it must always be considered a possibility.
• See the articles in the Forgery folder for examples of real-life cases and anecdotal estimates of the extent of the problem.
• The article “Detection of Forged and Fabricated Latent Prints” suggests that most fingerprint examiners are very poorly prepared to detect fabricated evidence.
3. Hire your own defense expert to examine the evidence. Since there is ample evidence to suggest that state-employed fingerprint examiners may be subject to unconscious prosecution bias, it is mandatory that you retain your own fingerprint examiner. Courts should approve these expenses as part of the right to counsel. You should ask that your defense expert be permitted to examine the original evidence and any displays that the government intends to use in court. Ask your defense expert to point out and dissimilarities or weak similarities in the government’s evidence.

How do I choose a defense expert?

Many defense attorneys ask this question, and there is no easy answer. In terms of skill, he only objective criterion that might indicate the quality of a latent fingerprint examiner is the International Association for Identification’s Latent Print Certification program. Unfortunately, the IAI certification program is controversial, and many fingerprint examiners claim that it is not an accurate indicator of skill. Nonetheless, in the absence of anything else to go on, attorneys may want to favor a certified examiner. Check the Defense Experts folder

·       The IAI maintains a list of certified examiners available for consulting.

·       There is also a list of non-certified examiners available for consulting.

After certification, you want to look for independence. There is anecdotal evidence that defense experts may “rubber-stamp” the government expert’s opinion, especially if they know the examiner personally. Unfortunately, there is at least one known case in which even a defense expert has confirmed a fingerprint matches later determined to be erroneous.

·       See the article “A Miscue in Fingerprint Identification” in the Documented Cases of Misidentification folder on this case.

Therefore, it is wise to seek a defense expert unaffiliated with the agency which effected the identification and unacquainted with the individual who made the identification. Thus, even if your defense expert corroborates the match that does not necessarily mean the print belongs to your client. Therefore, you need to consider . . .

4. Challenging the admissibility of forensic fingerprint evidence. Forensic fingerprint identification may be challenged under Daubert or Frye. Thus far, such challenges have enjoyed limited success. A Daubert challenge was temporarily sustained in U.S. v. Plaza and then rescinded under reconsideration. The dissent in U.S. v. Crisp (see Cases folder) held that fingerprinting should be inadmissible. Admissibility challenges are time-intensive. Since this is by far the most complex of the lines of attack covered here, it will be treated in the most detail.
• If you are in a Daubert jurisdiction, start with one of the briefs from U.S. v. Mitchell.
• There are several California briefs in the Cases folder.
• Frye jurisdictions, check the Frye folder.
• Among the most important sources are the fingerprint chapter of Modern Scientific Evidence and Stoney’s chapter in Advances in Fingerprint Technology, both in the Books folder.
• Review the Articles folder. Among the most useful pieces are “Fingerprints Meet Daubert,” “A Probablistic Approach to fingerprint Evidence,” and “Error Rates for Human Latent Fingerprint Examiners.”
• The government may proffer the “50K X 50K study” in support of the scientific validity of forensic fingerprint identification. This study has been discredited in the scientific literature. See the “50K X 50K study” folder for these articles.
• Call an scientific expert to testify at a Daubert/Frye hearing on the admissibility of fingerprint evidence. See the Scientific Expert folder.

Even if you lose an admissibility challenge, you still have more options open to you . . .

5. Informed cross-examination. Like Daubert says, “Vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence. Some of the points to cover during an effective cross-examination might include:

·       Apparent dissimilarities between the two prints.

·       What standard the examiner adheres to for declaring a match.

·       Education, especially scientific education, and training of examiner.

·       Is the examiner certified? If not, why not? Has the examiner taken and failed the certification examination?

·       Proficiency testing for the examiner individually and the laboratory as a whole.

·       Use the articles in the Articles folder as learned treatises, especially “A Probablistic Approach to fingerprint Evidence.” Same with Stoney’s chapter in Advances in Fingerprint Technology in the Books folder. Ask the examiner to address the criticisms of fingerprint identification contained in those treatises.

6. Call a scientific expert to testify to the limitations of forensic fingerprint identification. While some courts have not permitted such experts to testify at trial, many have.

·       See the Scientific Expert folder.

·       See the 3^rd Circuit brief in U.S. v. Mitchell for the argument that defendant has a right to call scientific experts.

7. Compare your local crime laboratory or fingerprint examiner to the standards for the FBI laboratory recognized in U.S. v. Plaza. While Plaza II upheld the admissibility of forensic fingerprint evidence, it did so specifically and exclusively with regard to the FBI laboratory. In doing so, it noted that the FBI had extensive (though poorly designed) proficiency testing and strict (though post-hoc) training and educational standards. You may discover data on your laboratory’s proficiency testing program, educational and training requirements (and whether examiners actually meet these requirements), and laboratory procedures manual. You may seek to show that your local laboratory falls short of the standards recognized in Plaza.

·       See the Protocols folder.

·       See the Proficiency tests folder.

8. AFIS. AFIS stands for Automated Fingerprint Identification System. This is a computer database of fingerprint images that has replaced the old card files. At booking images of suspects’ fingertips are scanned into the computer, but inked cards can be scanned in as well. Unidentified latent prints can be scanned into the system and searched against the database. The search can be global, or it can be limited by various parameters (sex, race, age, pattern type, etc.). The AFIS uses an algorithm to generate a similarity score for the comparison of the unidentified latent to each database print. The AFIS then produces a list of candidate matches. The AFIS can either be asked to display all prints that generate a similarity score above a certain threshold, or it can be asked to display the best 10 (or 20 or 30, or whatever the operator chooses) matches. The candidate matches are then examined on the computer screen by a human examiner. It is the human examiner who makes the final determination whether the latent print matches one of the database prints. The print that the human examiner decides matches may or not be in the first position on the candidate list.

The defense attorney should file a discovery request for the AFIS results. Did the AFIS place your client’s print in the first position? If not, have the examiner explain why not? Does the examiner know better than the computer? Have your defense examiner look at the database print that did appear in the first position. Was the AFIS search run more than once? Were there different results? What explains the different results?

9. Are there other novel issues? Was the latent print “digitally enhanced”? Were two latent prints “digitally combined”? These novel techniques are challengeable under Daubert/Frye.

·       See the Digital Enhancement folder on challenging digital enhancement.