Pennsylvania prosecutors use TrueAllele in homicide guilty plea

Back to Trials

State of Maryland v Nelson Clifford

"Consent defense" serial rapist finally convicted by DNA

Crime On September 30, 2007 a man broke into a woman's Baltimore home and sexually assaulted her.
Evidence A green shirt and a brown belt were recovered from the crime scene. These articles of clothing belonged to the victim's boyfriend, but were handled by the assailant. The rapist bound the victim's hands with the belt during the assault.
DNA The Baltimore City Police Department crime laboratory developed DNA data from the two evidence items. The data showed mixtures containing DNA from at least 3 people.
Match The crime lab's manual mixture analysis gave inclusion statistics in the thousands between the two evidence items and Nelson Clifford.
Defendant "The nature of the crimes Clifford has been accused of, and the sheer number of times he has been accused of committing them, is staggering," said State’s Attorney Marilyn Mosby. Clifford was first convicted at age 18 in 1997 of sexually assaulting a woman at knife point.

After Clifford’s release from prison in 2007, he allegedly committed nearly a half dozen sexual offenses, 4 of which he was found not guilty. At each trial – despite DNA evidence linking him to his victims – he was acquitted after taking the stand and claiming the sexual contact between him and his victims was consensual.
TrueAllele The computer separated the DNA mixtures into their three genetic components. Comparing these evidence components with reference samples, TrueAllele found the victim and boyfriend's DNA on the clothing. The computer also tied the evidence to Clifford, with a match statistic of 115 thousand to the brown belt, and a statistic of 182 thousand to the green shirt.
Cybergenetics    On May 7, 2015, Cybergenetics chief scientist Dr. Mark Perlin testified in the Baltimore trial about the TrueAllele match statistics.

As in his previous rape trials, Clifford testified in his own defense. He told the jury that the encounter was consensual. Clifford claimed that the victim, a second-grade teacher, was a prostitute whom he paid for sex.
Outcome The jury convicted Clifford of third-degree sex offense and theft. In light of his prior conviction, he was sentenced to over 30 years in prison.
Media
Back to top