Biomechanics, Number Of Lacerations Could Be Of Interest To Peterson Jury
Posted October 9, 2003
Updated December 9, 2006
DURHAM, N.C. — During Thursday's deliberations, jurors in the Mike Peterson murder trial asked for transcripts of testimony from two expert witnesses, North Carolina Chief Medical Examiner John Butts and John McElhaney, professor emeritus of engineering at Duke.
Both men were called by the prosecution as rebuttal witnesses to dispute defense claims that Peterson's wife died from a fall and not from a beating. The testimony of both men seemed to bolster the prosecution's case.
Judge Orlando Hudson did not allow the jury to read that testimony, telling them they would have to continue deliberations without those transcripts.
What could the jury have been interested in seeing in those transcripts? Here is a summary of each man's testimony, which may provide a clue as to what jurors were thinking or discussing.
John Butts, Chief Medical Examiner Of N.C., was the final prosecution witness to testify. He appeared on the final day of testimony. He was called to confirm what prosecutors said physical evidence showed about Kathleen Peterson's injuries, and to support the testimony of Dr. Deborah Radisch.
Radisch performed the autopsy on Kathleen Peterson. Butts is her supervisor.
Butts supported Radisch's contention that the number and severity of Kathleen Peterson's head wounds indicated a beating as opposed to a fall.
Butts counted seven head lacerations, three more than what the defense claimed. He identified each laceration on a photograph of the back of Kathleen Peterson's shaved head, marking each one with a ballpoint pen and counting them -- one to seven -- out loud.
"You don't just get lots and lots of lacerations across the back top of the head," Butts said from the stand.
Butts also disputed earlier claims by defense witness Dr. Henry Lee that blood found in the stairwell of the Petersons' home could have been coughed up by Kathleen Peterson as she fell, instead of being spatter from a beating. Butts said there was not enough blood in her lungs at the time of the autopsy to indicate that.
Butts said there was only one small portion of Peterson's lungs in which blood was present. He held up a slide to point out what he called "pin-head sized" specks in that one portion. Jurors passed the slide around, looking at it through a magnifying glass Butts had supplied.
"In my opinion, there's no evidence of any significant aspiration of blood," Butts said.
Butts admitted to defense attorney David Rudolf that a combination of alcohol, valium, muscle relaxant and antihistamines -- which was found in Kathleen Peterson's blood -- could have made her dizzy enough to fall down the stairs. But he maintained that it was very unlikely Kathleen Peterson died from a fall.
James McElhaney, Duke Emeritus Professor Of Engineering
McElhaney, an expert in biomechanics, testified over a couple of days. He was brought in a day after the defense rested its case, specifically to rebut the defense testimony of injury biomechanics expert Faris Bandak, who said Kathleen Peterson's injuries indicated an accidental death.
"The injuries, lacerations, bruises and contusions, in my mind, are inconsistent with a fall down the steps and are consistent with a beating with a blunt instrument," McElhaney testified, "most likely a rounded blunt instrument."
McElhaney said he based his conclusion on six aspects of Kathleen Peterson's injuries: 1) the location of the injuries, 2) the length of the injuries, 3) the number of injuries, 4) the "orientation" of the injuries, 5) the velocity that was needed to cause the injuries. and 6) the "amount of energy" needed to generate that velocity.
"When I put all of these things together, I conclude that the lack of skull fracture and brain injury . . . this was a relatively light object striking the head at the maximum velocity for laceration," McElhaney testified. "It was not a fall down the steps, which I would also expect to cause brain injury and skull fracture."
Just as Butts did, McElhaney left open the possibility that Kathleen Peterson's head could have been injured by striking the doorway molding and stairs as she fell, or by falling down on the stairs twice, or by each fall causing multiple lacerations. But he was quick to call that theory "a stretch."