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Jurors hear from DNA expert on their findings in Prentice Foreman trial update

Posted at 6:58 PM, May 20, 2019
and last updated 2019-05-20 21:58:59-04

BAKERSFIELD,Calif. — On Monday jurors heard expert witness testimony from Carol Williams and Garret Sugimoto. They are two of the DNA analysts who handled DNA samples collected from the murder case of 18-year-old Dawn Koons.
She was found killed and assaulted in her bathtub in 1979.

Gina Pearle, prosecutor for the case, focused the probability of how the DNA evidence found in the samples removed from Dawn Koons could belong to Foreman and was explained by Garret Sugimoto, DNA technical expert.

"What is the name of the person from the Codis Database who hit as a major contributor to the potential major contributor to this vaginal slide," said Pearle.

“It was Prentice Forman,” added Sugimoto.

"The probability of selecting someone random from the African American population group that would have the DNA profile that we detected in the major portion of this sample is 1 in 8.3 quintillion,” said Sugimoto.

Sugimoto further explained the delay of some of the DNA testing didn't occur until 2017 due to new technology that wasn't available until then.

Dana Kinnison, the defense, argued the accuracy of the DNA collected and questioned why some of Koons DNA was found mixed within some of sperm DNA findings.

"Is this a result you would expect in a low amount of sperm in the matter that you are analyzing,” said Kinnison.

“I would say so in this sample there was not enough DNA to obtain a full sample profile,” said Sugimoto.

"Females do not produce sperm correct,” said Kinnison.

“Correct,” said Sugimoto.

“So how can a female be a minor contributor to a sperm cell fraction,” said Kinnison.

Kinnison argued the accuracy of the DNA collected and questioned why all four DNA samples of Koons DNA was found mixed within some of the sperm DNA findings. “We do the best we can to make sure that we clean up any non-sperm cell fraction that may remain sperm fraction,” said Sugimoto. “And we do expect that in some cases non sperm cell contributor to carry over to that non sperm fraction- even though we are trying to be as careful as we can.”

The trial is scheduled to continue Tuesday, with three more additional expert witnesses. On Thursday the court will be visiting the location of the actual murder.