There is zero tolerance for friction ridge identification error in forensic science. Ignoring standards causes errors. A minimum number of Galton detail "points" does NOT equal an identification standard. The standard for identification is not a number. As demonstrated below,
relying on a specific number of allegedly
matching "points" can be a formula for disaster. The misleading comfort
of a "number" can lead Examiners (and Police administrators) to ignore more
important factors which insure reliability.
Friction ridge identification is a reliable science. Since the mid-1970's the International Association for Identification (IAI) and its Latent Print Certification Board have worked with state and regional chartered IAI Divisions throughout the U.S. toward the goal of improving professional abilities. Since 1995 the Federal Bureau of Investigation has sponsored the Scientific Working Group on Friction Ridge Analysis, Study and Technology (SWGFAST) for developing consensus standards which preserve and improve the quality of service provided by the latent print community nationwide. During 1995 through 1997 American Latent Print Examiners established minimum qualification, training and quality assurance SWGFAST guidelines through review, discussion and feedback at local and national meetings, and through peer review in professional journals. Latent Print Examiners are able to reliably make positive identifications: 1. With appropriate training (SWGFAST training content guidelines); Analysis – the qualitative and quantitative assessment of Level 1, 2 and 3 details to determine their proportion, interrelationship and value to individualize. Friction ridge identification reliability is insured by Training, Experience and Ability coupled with ACE-V to effect a positive identification when sufficient quality (clarity) and quantity of corresponding Level 1, 2 and 3 detail exists. Quality (clarity) and quantity vary with each friction ridge impression. Analysis is objective. Comparison uses objective observations. The final identification decision is subjective and is reached when sufficient quality (clarity) and quantity of corresponding Level 1, 2 and 3 friction ridge details are present. The quality (clarity) and quantity of details necessary to effect the identification can vary based on training, experience and ability of the Latent Print Examiner. Even though each latent print can have different quality (clarity) and quantity of Level 1, 2 and 3 details... Latent Print Examiners with similar training, experience and ability should be able to identify the same latent and inked prints.
Quality assurance and quality control guidelines exist to detect erroneous friction ridge impression identifications. The Examiner making the error is immediately suspended from casework activity. Remedies to insure operational reliability include the following:
David Ashbaugh's important Ridgeology publication defines Level 1, 2 and 3 details and explains in plain language the scientific methodology called ACE-V in use by Latent Print Examiners worldwide. |
The Acceptable
Error Rate for Friction Skin Identifications is ZERO
If you are a Latent Print Examiner, you know the above statement to be true. If you are an attorney, police administrator or other non-expert, this may sound unrealistically strict. Scientists generally concur that a reliability of 95% constitutes scientific certainty (1), (2). In many areas of science and many professions, such reliability serves society well. For example, the acceptable error rate for Chicken Sexers (persons who examine the backsides of one-day-old chicks to sort males from females) is between 2.3 and 5 percent when examining 700 to 800 chicks per hour. |
| As
an expert working in fingerprints since 1971, I have seen some of the skeletons
in my discipline's closet. In the below paragraphs you can read my
personal reasons for building this page. I was lucky in that I did
not encounter the degree of opposition the Scottish Criminal Records Office
(SCRO) has given Pat Wertheim and David Grieve. I appreciate the knocks
they are taking (SCRO criticism and belittling)... it may be easier for future
experts in a similar situation. --Ed German
Sixteen years ago, a friend of mine (a Latent Print Examiner from Illinois) brought me the charts shown above in the "Illinois case." That same day I (and coworker Steve Kasarsky) caused an incarcerated prisoner to be freed and charges dropped because we pointed out the error. The wrongfully incarcerated prisoner was on parole from prison. The Latent Print Examiner, being relatively new in the business, had not previously caused anyone's incarceration based upon fingerprint evidence and the Prosecutor decided that no future warrants would be issued based on just the local examiner's work. The Illinois "Latent Print Examiner" was decertified and continued working as a policeman and crime scene technician. He is still employed by the same agency and to my knowledge has since always submitted fingerprint identifications to outside agencies for verification. I do not reveal the city here because I am proud of his integrity and professionalism. Thirteen years ago, a Latent Print Examiner from Fayetteville, North Carolina brought me a crime scene mark for "computer enhancement" because he was having trouble charting it for upcoming court. The person "identified" was an active duty US Army staff sergeant who at the time had been in jail for over a year awaiting trial on murder charges. The latent fingerprint was in blood, from the doorknob of the bedroom where the body was found. I told the Fayetteville Latent Print Examiner that no enhancement in the world would ever change the fact that the bloody print was not made by the suspect. He said that he wanted a second opinion and I sent him immediately to Marty Ludas in Raleigh, North Carolina who also told him that it was a "bum ident." Despite assurances to both me and Marty Ludas that he would immediately tell the prosecutor, we later learned that the expert allowed the incorrectly identified sergeant to stay in jail another two weeks, until the morning of the start of the murder trial. On the morning jury selection commenced for the trial, the Latent Print Examiner told the Prosecutor that although there was enough similarity in the latent print to make a tentative identification... he had determined just recently that it was NOT a positive identification. This was a ludicrous remark (tentative identification upon which to base arrest), one I have never heard since. The charges were dropped on the spot and the Sergeant freed right there in the courtroom. When I learned of the sequence of events, I immediately contacted the Prosecutor and Chief of Detectives in Fayetteville to relate that the error had been revealed two weeks earlier. Also, because the erroneous "expert" was self-trained and was the trainer for the only other "expert" in his office (the blind leading the blind regarding expertise), I urged the Chief of Detectives to have 100% of all their prior casework reviewed by outside experts. The local police balked at my suggestion and told me that their "expert" said it was a once in a lifetime error and that I was just attacking him and his coworker because they refused to participate in the IAI's certification testing program. I continued to assert that where there is smoke, there is fire. After several calls and formal letters to the local police and Prosecutor, I finally "won" and it was decided that no new warrants would be issued based on the "LP Examiners'" reports until completion of an outside review of all their casework. The North Carolina state crime lab declined to participate, but Robert Hazen, Senior Expert at the FBI's Latent Fingerprint Section, agreed to supervise the 100% review by his subordinate experts. The review revealed a number of serious errors, including a couple of erroneous fingerprint identifications involving "elimination" prints of police and victims... and also revealed that valid identifications against suspects in serious crimes had been missed. Nobody else was freed from jail, but I still felt vindicated from the claims I was persecuting the two "experts." The last I heard, both "experts" had left the agency and the senior of the two was teaching forensic science at the local community college. I know that fingerprint (friction skin/ridgeology) experts perform an invaluable service to society. I also believe that quality control/assurance and other checks and balances such as international peer review must exist to insure the discipline's reliability. In the Illinois case the wrongfully accused was immediately released. In the Fayetteville, North Carolina case, I have always regretted that the Army sergeant spent an additional two weeks in jail because I trusted the expert to notify the Prosecutor immediately. It taught me a lot about "expert" egos and recalcitrance related to exposing serious error. If you are an expert and have knowledge of an erroneous identification impacting a person's liberty or reputation you must "do what has to be done" (my agency's motto) to inform the investigators in charge of the case... and verify timely notification to the Prosecutor and/or Defense/Court. If you are an expert and have additional examples of erroneous identifications you think might benefit the discipline through Internet posting, please e-mail me. --Ed German, CLPE, FFS
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