21-Jun-2012

Cybergenetics matches DNA mixture to Virginia man convicted of child abduction and assault

Fairfax, VA

Jonathan Nathaniel Ramsey, 16, was convicted of attacking a five year old Springfield girl. In the dark early hours of August 27, the child was abducted from her home, molested in the nearby woods, and repeatedly stabbed with a kitchen knife. The girl's blood was found on boxer shorts and a T-shirt in Mr. Ramsey's backyard. DNA mixtures containing the victim and at least one other person were also found on the clothing, but human review of the data could not produce a match statistic.

At the trial, Cybergenetics Dr. Mark Perlin explained how a TrueAllele® computer interpreted the DNA mixture evidence. The Pittsburgh scientist showed the jury how the computer thoroughly examined the lab's DNA data, objectively inferring results without knowing the defendant's DNA profile. Dr. Perlin testified that a match between the boxer shorts and Mr. Ramsey was 916 million times more probable than coincidence. He further testified that a match between the T-shirt and Mr. Ramsey was 3,200 times more probable than chance.

The evidence established that Mr. Ramsey and the girl had both left DNA on the clothing. The jury convicted him of abduction with intent to defile and malicious wounding, among other charges. Mr. Ramsey was tried as an adult, and faces life imprisonment when he is sentenced in September.

• Fairfax girl, 5, abducted from bedroom, assaulted - Washington Post
• Five-year-old girl abducted from Springfield home - NBC News
• Springfield neighborhood on high alert after child abducted from bedroom - WUSA9 News
• Trial begins for teen accused of abducting and assaulting child in Fairfax County - Washington Post
• Jonathan Nathaniel Ramsey convicted of attack on 5-year-old Springfield girl - Washington Post