Head of D.C. crime lab defends analysis of DNA data

In the wake of criticism from federal prosecutors, the head of the Districts new crime lab stood behind his labs analysis of DNA data Thursday but told a key D.C. Council member that his lab is understaffed.

The method we use is the most common method used by many labs around the country, including the FBI, Max M. Houck, director of the lab, said during testimony at the councils Judiciary Committee oversight hearing.

The D.C. lab, which is in a $220million facility in Southwest Washington that opened in 2012, has come under scrutiny after prosecutors said they found critical errors in the DNA work at the lab. The U.S. Attorneys Office has stopped using the lab to evaluate evidence, instead opting to use outside labs. It also has hired independent DNA experts to review 116 cases previously examined by the city-run lab.

Both the U.S. Attorneys Office and D.C. Mayor Muriel E. Bowser (D) have initiated separate audits of the lab and its work. Houck said that his lab has been audited five times in the past two years and that he welcomed the reviews.

The dispute between federal prosecutors and the citys Department of Forensic Sciences was first reported last week by The Washington Post.

During the hearing, Houck, as he has in the past, repeatedly defended the work by his lab and disputed that there were any errors. He argued that the other labs and experts hired by prosecutors were merely interpreting analyses differently than his scientists were. The biggest problem, he said, is that the lab does not have enough staff to keep up with demands. To me, a critical error is the wrong person in jail or the right person not in jail, he said. We provide information that is one of many tools to help make that decision.

Prosecutors say the purported problems with DNA analyses have not led to any exonerations or any charges being dismissed. Attorneys say the dispute could trigger appeals or civil lawsuits, but the impact ultimately will depend on how important DNA evidence was in each case.

The dispute centers on the analysis of samples that include DNA from more than one person.

The lab, prosecutors allege, understated or overestimated the likelihood that a particular persons DNA was left at a crime scene. In one federal case, prosecutors said, the D.C. lab concluded that a defendants DNA could have been on the magazine of a gun seized as evidence. But an expert who reviewed the data said the lab should have interpreted the results to mean that the defendant was not the source of the DNA.

Houck noted that various labs have different ways of interpreting data from DNA mixtures.

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Head of D.C. crime lab defends analysis of DNA data