A Review of the FBI's Handling of the Brandon Mayfield Case, unclassified executive summary. Reason #2

The 2nd. significant factor noted by the OIG was the examiners of some features adjusted or influenced by "backward " reasoning. In effect after determining 10 points of "unusual similarity" the examiners found additional features by working backward from Mayfields file print. The examiners found features in the exemplar and then looked for them in the latent image resulting in "murky or ambiguous details" being erroneously identified as points. When an examiner is dealing with a poor quality latent that lacks clarity, it is tempting to look at the exemplar and work backward but as is clear from the Mayfield case it can have disastrous results. This backward or circular reasoning allowed the examiners in Mayfield to report up to 17 points of identification. A jury or defense attorney presented with a case like Mayfield would be ill equipped to determine that an error had occur ed and then convince a jury of the error.

If you watch any of the shows that highlight current criminal trials ,you'll often hear the analyst talk about having 8 points in fingerprints as a standard, they indicate if there are 8 points the print is an identification. I would suspect many lawyers are under the same impression that if there are 8 points case closed, as we see in Mayfield this is not the case. I would also go back to the point I've made numerous times in the past; the examiners in the Mayfield case all had more training and experience than most examiners testifying in court today. Even highly experienced latent examiners with training can make an identification error, the only way to prevent the error from causing disastrous on sequences is to have the evidence evaluated by an experienced examiner.

Bob McAuley
Dir. Operations/Training
Forensic Biometric Identification Solutions LLC.

Additional Point on Item 1 of the FBI Report

One other point I would like to make so it's not lost in item 1 of the FBI report. The 10 of the points of identification finally used to identify Daoud,were also used by the FBI to incorrectly identify Mayfield. Why is this significant? most cases of fingerprint identification accepted in court today are brought in by latent examiners with less experience and training than the FBI examiners. With no "systematic study of the rarity" of finding such a constellation of similar points of identification, how can we expect less experienced examiners to make identifications on similar difficult identifications.

Bob McAuley
Dir. Operations/Training
Forensic Biometric Identification Solutions LLC.

A Review of the FBI's Handling of the Brandon Mayfield Case, unclassified executive summary.

Went back over the executive summary on the Mayfield error back in 2004 and want to discuss what the Office Inspector General determined were the causes of the error as well as what the OIG suggested to prevent similar errors in the future.
The report listed six (6) causes for the error and in this blog I'd like to discuss the 1st. major contributing factor in the error. The OIG found the primary cause of the error was the similarity in Mayfield's print with the latent found in Spain. " Despite the unusual similarity in the relationship between points on the Mayfield and Daoud prints, Mayfield and Daoud did not have identical fingerprints." It also pointed out there are no studies on how often situations similar to this occur but anecdotal reports this as a rare occurrence. The identification was an IAFIS suspect and as the OIG pointed out "The enormous size of the IAFIS database and power of the IAFIS program can find a confusingly similar print." The OIG in my opinion was correct in highlighting this as the major factor in the error. As databases increase and algorithms improve there will be more suspects produced, that will have unusual similarity between points but will not be the individuals print.
So can this type of error be prevented ? There will continue to be similar errors we can minimize the numbers with training and utilization of fingerprint experts for the defense. In the Mayfield case you had four (4) experienced and well trained fingerprint examiners that made this bad identification.


Bob McAuley
Dir. Operations/Training
Forensic Biometric Identification Solutions LLC.