we look at the fingerprint-related portion of the unclassified report of the US Department of Justice Office of the Inspector General (OIG) involving a Review of the FBI's Handling of the Brandon Mayfield Case.

_________________________________________
*Below is the outline with key sections of this report only
The complete report is available online at:
http://www.usdoj.gov/oig/special/s0601/final.pdf
(http://www.usdoj.gov/oig/special/s0601/final.pdf)

(Starting at p. 6)

IV. OIG Assessment of the Causes of the Misidentification

In this section of the executive summary, we discuss the OIG's assessment of the causes of the FBI Laboratory's misidentification of LFP 17.

A. The Primary Causes of the Error

The OIG found several factors that caused the FBI's misidentification of the fingerprint.  The unusal similarity between LFP 17 and Mayfield's known fingerprint was a major factor in the misidentification that confused three experienced FBI examiners and a court-appointed expert.  However, we concluded that the examiners committed errors in the examination procedure, and that the misidentification could have been prevented through a more rigorous application of several principles of latent fingerprint identification.

    1.  The unusual similarity of the prints

In identifying Mayfield as the source of LFP 17, the FBI examiners relied in significant part on the relationship of "minutiae" or "points" within the prints.  (...)  Ten of the points in LFP 17 that were used to identify Mayfield were also later used by different FBI examiners to identify Daoud as the source of the print.  These 10 features in LFP 17 formed a constellation of points that was generally consistent with the constellation of points in the known fingerprints of both Mayfield and Daoud.  The unusual similarity is reflected in the relative location of the points, the orientation of the ridges coming into the points, and the number of intervening ridges between the points.  Although the OIG found no systematic study of the rarity of such an event, anecdotal reports suggest that this degree of similarity between prints from two different people is an extremely unusual circumstance.
(...)
In addition, the Mayfield case illustrates a particular hazard of the IAFIS computer program.  (...)

    2.  Bias from the known prints of Mayfield

(...) The OIG found that a significant cause of the misidentification was that the LPU examiners' interpretation of some features in LFP 17 was adjusted or influenced by reasonong "backward" from features that were visible in the known prints of Mayfield.  (...)  The FBI examiners began to "find" additional features in LFP 17 that were not really there, but rather were suggested to the examiners by features in the Mayfield prints. (...)

    3.  Faulty reliance on extremely tiny (Level 3) detials

The OIG also found that FBI examiners gave significant weight to the purported agreement between extremely tiny details in LFP 17 and Mayfield's fingerprint.
(...)
The OIG found that none of the purported Level 3 features in LFP 17 used to identify Mayfield corresponded to features in the known prints of the true donor (Daoud).  Thus, unlike the case with larger details, the examiners were not confused by any unusual similarity in Level 3 details on the fingers of Mayfield and Daoud.  Rather, they apparently misinterpreted distortions in LFP 17 as real features corresponding to Level 3 details seen in Mayfield's known fingerprints.
(...)

    4.  Inadequate explanations for differences in appearance

(...)  Although the explanations that the examiners gave for each difference were individually plausible, they cumulatively required too many rationalizations to support an identification with the requisite certainty.  The OIG concluded that the FBI examiners did not apply a sufficiently stringent standard for their explanations and thereby failed to appropriately apply the "one discrepancy rule."

    5.  Failure to assess the poor quality of similarities

The OIG also found that the FBI examiners failed to give adequate consideration to the incomplete nature of the agreement in points between LFP17 and Mayfield's fingerprint.  (...)  The OIG found that many of the points utilized by the FBI to support the identification suffered from ...(ambiguity as to feature type), and that accordingly the "quality" of the agreement was inadequate to support the conclusion of identification.

    6.  Failure to reexamine LFP 17 following the April 13 Negative Report (of the Spanish
         National Police)

The FBI Laboratory missed an opportunity to catch its error when the SNP informed the FBI on April 13 that it had reached a "negativo" (negative) conclusion with respect to matching LFP 17 to Mayfield's fingerprints.  (...)  A better response to a conflicting determination by another forensic laboratory would have been first to determine the complete basis for the other laboratory's disagreement before committing anew to the validity of the original determination, and also to arrange for a fresh examination of the relevant prints by a new examiner who had not previously committed himself to a particular conclusion.  The FBI Laboratory took neither of these steps.

B.  OIG Assessment of Other potential Sources of Error

First, the OIG examined whether the ("Ridgeology Standard") used by the FBI Laboratory for declaring an identification contributed to the error. (...)  The OIG concluded that the error would not necessarily have been avoided by the application of a Numerical Standard. (...)

Second, the OIG examined whether the FBI's verification procedures (lacking blind verification) contributed to the error. (...)  The OIG did not find compelling evidence that the FBI's verification procedures introduced a bias that prevented or discouraged the official verifier from challenging the identification in this case. (...)

Third, the OIG considered whether the pressure of working on a high-profile terrorism case was a significant contributing cause of the error in this case.  We found no evidence to support this conclusion.
(...)

C.  The Role of Mayfield's Religion in the Identification

The OIG also investigated whether the FBI fingerprint examiners were aware of and improperly influenced by knowledge of Mayfield's religion when they made the identification of LFP 17.  We determined that the FBI examiners were not aware of Mayfield's religion at the time they concluded Mayfield was the source of LFP 17.
(...)

D.  Explanations Found by the OIG Not To Have Contributed to the Error

(...)
First, the OIG reviewed the initial claim that the FBI's lack of access to the original evidence on which LFP 17 was deposited was a cause of the error. (...) The OIG reviewed the evidence and concluded that, contrary to the FBI's claims, having access to the bag would not necessarily have prevented the LPU from misidentifying Mayfield.

FBI spokespersons also offered another explanation immediately after the error was discovered: that the FBI was working with a degraded or distorted third-generation digital image of LFP 17 provided by the SNP.  The OIG found that although there was a modest improvement in clarity in the photographic image of LFP 17 that the SNP eventually made available to the FBI, the quality of the digital image initially supplied to the FBI did not cause the error.
(...)

We also considered the suggestion by some members of the International Panel that the FBI examiners were misled by an excessive faith in the IAFIS technology.  The OIG did not find this explanation to be persuasive.  (...)

OIG RECOMMENDATIONS:

Develop criteria for the use of Level 3 details to support identifications

Clarify the "one discrepancy rule" to assure that it is applied in a manner consistent with the level of certainty claimed for the latent fingerprint identifications

Require documentation of features observed in the latent fingerprint before the comparison phase to help prevent circular reasoning

Adopt alternate procedures for blind verifications

Review prior cases in which the identification of a criminal suspect was made on the basis of only one latent fingerprint searched through IAFIS

Require more meaningful and independent documentation of the causes of errors as part of the Laboratory's corrective action procedures.

(...)

______________________________________________________________________
Feel free to pass The Detail along to other examiners.  This is a free newsletter FOR latent print examiners, BY latent print examiners. There are no copyrights on The Detail, and the website is open for all to visit.

If you have not yet signed up to receive the Weekly Detail in YOUR e-mail inbox, go ahead and join the list now so you don't miss out!  (To join this free e-mail newsletter, enter your name and e-mail address on the following page: http://www.clpex.com/Subscribe.htm  You will be sent a Confirmation e-mail... just click on the link in that e-mail, or paste it into an Internet Explorer address bar, and you are signed up!)  If you have problems receiving the Detail from a work e-mail address, there have been past issues with department e-mail filters considering the Detail as potential unsolicited e-mail.  Try subscribing from a home e-mail address or contact your IT department to allow e-mails from Topica.  Members may unsubscribe at any time.  If you have difficulties with the sign-up process or have been inadvertently removed from the list, e-mail me personally at kaseywertheim@aol.com and I will try to work things out.

Until next Monday morning, don't work too hard or too little.

Have a GREAT week!