DEMOCKER TRIAL: Defense expert: DNA at crime scene could be Knapp's
PRESCOTT - A law enforcement report said only the victim's DNA could be identified at the crime scene, but the defense in the Steven DeMocker murder trial on Wednesday called to the stand an expert who said that wasn't accurate.
DeMocker is accused of killing his ex-wife, Carol Kennedy, in July 2008. He's maintained his innocence from the start, and his lawyers have argued that there was another viable suspect, James Knapp, who was never thoroughly investigated.
Norah Rudin, Ph.D., an independent forensic DNA analyst from Mountain View, Calif., testified that the Arizona Department of Public Safety was too conservative in its analysis of blood found on a doorknob in Kennedy's home, where she was found bludgeoned to death.
Rudin said she investigates the "signal-to-noise" ratio in deciding whether matches are viable, and through the use of several charts, illustrated that, while Kennedy's DNA was clearly in the blood, it was also possible to name others, including Knapp.
DPS Supervising Criminalist Kortney Snider said in August testimony that the agency could not identify anyone other than Kennedy.
Rudin said, "Things change, and that's just a fact of science," noting that her technique, known as the "empirical threshold" has been described in forensic journals.
The blood swabbed from the door handle in Kennedy's home included DNA that she said was similar to James Knapp's and DeMocker's daughter, Katie's, DNA.
Under cross-examination by Deputy County Attorney Jeff Paupore, Rudin said that, as a scientist, she would not be willing to say it was a "match."
She did say that the DNA sample was "5,500 times more likely to be Knapp than an unknown person."
Paupore also wanted to know how Katie's DNA was found in the blood. He asked if a swab could pick up DNA left on the surface before the blood was deposited, and Rubin said it was possible.
Paupore noted that Katie had not been in the house for days, and asked if Knapp's DNA could also have been left there days earlier. Rubin again said it was possible.
Other testimony Wednesday came from Terri Haddix, MD, a forensic pathologist. She told the jury that she "didn't see the basis for (the) opinion" that a golf club - which the state argues was the weapon used - was certainly the murder weapon.
"I can't say with any degree of certainty what weapon was used," Haddix added. Her task was hampered, she said by the quality of the autopsy photos.
"They're not very helpful," she said, pointing out that what she called standard procedure was to shave the victim's scalp to allow doctors to see how the weapon affected the skin around the wounds.
Deputy County Attorney Steve Young asked if she could rule out a golf club.
"I can't exclude that,' Haddix said.
The defense may wrap up its case as early as today, according to attorney Craig Williams.
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