Based on testing of a swab taken from the victim's left breast, the Alaska crime lab was unable to exclude Justin Starkweather as the source of DNA found on the sample, a forensics expert told jurors in Kenai Superior Court on Thursday.
"No DNA foreign to (the victim) and Mr. Starkweather was present," said Abirami Chidambaram, DNA section technical manager for the state's Scientific Crime Detection Laboratory in Anchorage.
The lab tested DNA from the victim and from Starkweather for comparison with DNA collected at the crime scene.
Starkweather, 23, is charged with first-degree attempted murder, first-degree sexual assault, first-degree assault, first-degree burglary and fourth-degree theft in connection with a brutal sexual attack on a 46-year-old woman in her home near West Poppy Lane in 2002.
According to testimony in the trial, which began with opening statements Sept. 17, the woman was found lying on her back in a pool of blood on the floor of her bedroom, clothed in only a T-shirt.
Nearly every bone in her face was broken, she had been sexually assaulted and a chest of drawers was lying across her when she was found by a friend several hours after the attack.
The victim was rushed to Central Peninsula General Hospital and then flown to a hospital in Anchorage, where she remained on life support for a number of weeks.
During testimony Thursday, Chidambaram said the crime lab used a Promega Power Plex 16 DNA testing kit that compared 16 location points on the DNA chain of the sample. Power Plex is among the most advanced DNA tests used by law enforcement agencies across the country today.
One locus indicated that a male source was present. Thirteen of the other 15 loci showed the presence of chromosomal indicators from Starkweather and the victim.
At two of the loci, according to Chidambaram, the data was insufficient, so the data from those two was not used.
The sample was compared to the same 16 location points contained in known samples of DNA taken from the victim and from Starkweather.
The crime lab also ran a statistical analysis of the data and found that the chances of a Caucasian male contributing the DNA were 1 in 9,891. Chances the person was African-American were 1 in 168,000; Athabascan, 1 in 33,090; Inupiat, 1 in 181,200; and Yupik, 1 in 40,270.
During cross examination by defense attorney Cynthia Strout, Chidambaram said the question asked when doing the statistical analysis is: What is the chance a Caucasian male contributed to the mixture?
Strout asked if the biological sample could have been sweat, blood, saliva, hair or dandruff, and Chidambaram said, "We knew it was not blood. We did not do semen. We assumed it was saliva."
Strout then asked if the DNA could have been transferred onto the victim by someone during the nine hours between the time she was first found and when the sample was collected by the sexual assault nurse examiner in Anchorage.
"If the sample had been contaminated, we would have found DNA from a foreign source," the DNA expert said.
Strout asked if it were possible that if someone took an item of clothing that belonged to a person, wet it and rubbed it onto a person, the DNA could be transferred.
"That depends on many variables," Chidambaram said.
District Attorney June Stein later asked, "There was no DNA foreign to (the victim) or Justin Starkweather?"
"That's correct," Chidambaram said.
Before Chidambaram testified, another DNA expert from the crime lab, Hayne Hamilton, had said tests she performed with less sensitive technology available in 2002 indicated the presence of a male contributor, but the criteria was not high enough to determine if that source was Starkweather.
Hamilton also tested hand and fingernail scrapings from the victim, swabs from each breast, neck swabs and nail swabs.
She failed to exclude the victim from any of the samples and said DNA from a male was present on the left breast swab.
Testimony in the case is scheduled to resume at 9:30 in Judge Charles Cranston's courtroom today.
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