Tuesday, November 30, 2004

Human Error 

The following story is almost two weeks old, but we missed it -- and are therefore grateful to our esteemed colleagues at TalkLeft, who were on the job while we were nodding. The company in question, Cellmark, has provided DNA analyses in a number of notable criminal trials, including the JonBenet Ramsey inquiry and the O.J. Simpson case:
The alleged falsifying of DNA testing data by a former Montgomery County-based laboratory employee has exposed a vulnerability in computerized forensic analysis previously unknown to some experts, raising questions about the reliability of the most widely used and trusted method of testing.

The ex-Orchid Cellmark employee electronically manipulated the analysis in 20 tests, the company says. Though she did not alter the outcome of the tests, she overrode procedures designed to ensure the accuracy of the tests by substituting data in the known specimen, or control samples, according to Cellmark . . . .

The incident has prompted the public defenders in Los Angeles County to examine all pending cases in which Cellmark analyzed evidence.

"What had previously been represented was that you could not electronically manipulate the raw data. ... This wasn't just our belief, it was the belief of the relevant DNA experts in the field," said Patrick Kent, chief of the forensics division for the Maryland public defender's office, also reviewing cases in which Cellmark was used. "But that clearly is not the case" . . . .

In a September letter to the Los Angeles Police Department crime laboratory Robin W. Cotton, a director of technical forensic science for Cellmark, wrote that when a control test showed an "imperfect" profile and should have been reanalyzed, Blair instead substituted a con trol profile with no imperfections.

The letter stated that all of the affected cases have been re-tested, and the results of the original analysis remained the same.

However, the incident shows that the objective method of computerized testing can be compromised by the people conducting the analysis, Kobilinsky said.

"Underlying everything is a presumption of ethics," he said. "Electronic tampering of the results -- it's just unheard of."

As a result of the incident, Lutherville defense attorney Joseph Murtha said he will challenge the lab's credibility in future cases. He has a pending case in which Cellmark will perform the DNA analysis, and if the results are connected to his client, he will call for an independent review of the analysis.

Louis P. Willemin, deputy public defender for Maryland's Howard and Carroll counties, said an incident of alleged lab misconduct is "the defense's worst nightmare because it's not the easiest thing to find out."

"It's just a real significant problem when that happens because everybody is relying on [the analyst's] integrity," he said. "None of us are scientists."

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