Statement on Brandon Mayfield Case
After
the March terrorist attacks on commuter trains in Madrid, digital images
of partial latent fingerprints obtained from plastic bags that contained
detonator caps were submitted by Spanish authorities to the FBI for
analysis. The submitted images were searched through the Integrated
Automated Fingerprint Identification System (IAFIS). An IAFIS search
compares an unknown print to a database of millions of known prints.
The result of an IAFIS search produces a short list of potential matches.
A trained fingerprint examiner then takes the short list of possible
matches and performs an examination to determine whether the unknown
print matches a known print in the database.
Using standard
protocols and methodologies, FBI fingerprint examiners determined that
the latent fingerprint was of value for identification purposes. This
print was subsequently linked to Brandon Mayfield. That association
was independently analyzed and the results were confirmed by an outside
experienced fingerprint expert.
Soon after the
submitted fingerprint was associated with Mr. Mayfield, Spanish authorities
alerted the FBI to additional information that cast doubt on our findings.
As a result, the FBI sent two fingerprint examiners to Madrid, who compared
the image the FBI had been provided to the image the Spanish authorities
had.
Upon review it
was determined that the FBI identification was based on an image of
substandard quality, which was particularly problematic because of the
remarkable number of points of similarity between Mr. Mayfield's prints
and the print details in the images submitted to the FBI.
The FBI's Latent
Fingerprint Unit will be reviewing its current practices and will give
consideration to adopting new guidelines for all examiners receiving
latent print images when the original evidence is not included.
The FBI also plans
to ask an international panel of fingerprint experts to review our examination
in this case.
The FBI apologizes
to Mr. Mayfield and his family for the hardships that this matter has
caused.