Professor Criticizes Expert’s Testimony on DNA Evidence in Homicide Case

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A biostatistics professor criticized a forensic scientist’s testimony on DNA evidence involved in a homicide case before DC Superior Court Judge Todd Edelman on March 25.

Kavon Young, 34, is charged with first-degree murder while armed for his alleged involvement in the fatal shooting of John Pernell, 66. The incident took place on July 3, 2010, during a robbery at a cookout on the 3000 block of Nelson Place, SE. According to court documents, multiple armed men allegedly assaulted attendees and stole personal belongings.

In court, Mani Golzari, Young’s attorney, began his continued motion to exclude DNA evidence by calling a professor of biostatistics, who had evaluated the 14 studies the prosecution’s expert used to reach his opinions in the case.

The professor said she went through each of the 14 studies to try and find evidence that supported any of the four claims the expert was making in this case. She concluded that none of the studies speak to the four claims in a scientifically valid or supporting way.

The professor also said the studies relied on convenience, did not look at proper sample sizes, did not look at whether those samples were representative of the relevant population, and did not factor in potential uncertainty. She claimed the prosecution’s expert “made sweeping claims based on eyeballing studies” and not doing actual data analysis.

Golzari and the professor then went through each study, showing the court the problems prevalent in each one.

“The point of statistics isn’t that you eyeball two numbers, you run a hypothesis test,” she said. She ended by stating that these studies do not speak to the expert’s claims in a high quality manner.

A forensic DNA consultant also testified that he believed the prosecution’s DNA expert had used an inappropriate and outdated method of DNA analysis to reach his conclusions pertaining to DNA evidence found under fingernails in the case.

He cited articles from the National Institute of Standards and Technology (NIST) and the American Statistical Association (ASA) that supported his statements.

In response, the prosecutor said that just because you adopt new techniques, it doesn’t mean the old technique is obsolete.

Parties are slated to reconvene March 27.