In the Media

Fresh doubts over fingerprint evidence

PUBLISHED July 31, 2006

FRESH doubts over the accuracy of fingerprint evidence in courts has been raised by new research showing experts can be easily swayed in their judgements by "background" information.

The study found that experts can unwittingly "see what they want to see" when looking at scene-of-crime prints, resulting in wrong decisions which potentially could lead to miscarriages of justice.

Members of the Scottish Parliament's justice committee yesterday said the research has major implications for their inquiry into the Scottish Criminal Records Office (SCRO) and the Shirley McKie case and called on the report's author, Dr Itiel Dror, a psychologist at the University of Southampton, to submit his findings to MSPs.

The findings, contained in a report called Why Experts Make Errors, have also triggered calls for a comprehensive review of hundreds of convictions in Scottish courts based on fingerprint analysis.

In Dr Dror's experiment, six fingerprint experts from around the world were given eight "latent" crime-scene prints which they were asked to compare with sets of elimination prints.

The experts were unaware that they had previously examined the latent prints. Before viewing four sets of prints, each expert was given false information - it was either suggested to them that the prints were from the criminal or were eliminated from the inquiry when the opposite was true.

This "biasing context" led four of the six anonymous experts to change their minds and come to a different conclusion. One expert changed his mind three times.

Dr Dror told The Scotsman that his findings, published in this month's Journal of Forensic Identification, demanded an urgent review of procedures within national fingerprint services.

He said: "It could be that miscarriages of justice have occurred because of this basic problem. I believe in fingerprints as a tool for solving crime, but we need to minimise this bias. The service is doing very little, if anything, to minimise the cognitive bias, and that is deeply concerning.

"I'm not accusing anyone of lying - it's just how the brain works. We have to deal with it and learn from it."

The inquiry into the SCRO, prompted after ministers paid ?750,000 in damages to Ms McKie after she was wrongly accused of leaving her fingerprint at a murder scene, has heard that fingerprint experts are routinely given a list of "elimination" prints from detectives investigating a crime. The experts know in advance that police are keen to eliminate these names - usually fellow officers who were at the scene of the crime - from their investigation.

MSPs have also heard that, in the McKie case, experts viewing the controversial print left on the doorframe in the Kilmarnock house where Marion Ross was murdered knew that their colleagues had already decided the print belonged to the former Strathclyde detective.

Dr Dror said these types of procedures tend to be based on intuition rather than science and could expose fingerprint experts to dangerous levels of bias.

Bruce McPhee MSP, who sits on the committee, said the research provided scientific proof for the growing belief that fingerprint experts are subject to unacceptable levels of influence.

He added: "I think [the study] has major implications for the Scottish fingerprint service. This is very useful information. Dr Itiel Dror should be encouraged to submit his findings to the committee."

Ms McKie's father, Iain, called for the "books to be reopened" on previous SCRO fingerprint cases in light of Dr Dror's findings. A review of cases within a 12-month period was ordered after Ms McKie was acquitted of perjury, but Mr McKie said a more far-reaching review was needed to ensure no further mistakes have been made.

A spokeswoman for the Executive said a series of improvements had been made to the forensic fingerprint analysis since the McKie case. She said: "We are now determined to ensure that the Scottish Fingerprint Service (SFS) is recognised as truly world class."

David Mulhearn, interim head of the Scottish Police Services Authority and author of a new action plan for the SFS, added: "The reliability of a fingerprint identification is demonstrated by a strict verification process. The conclusions are proven to be valid through consistent results from different examiners."