Andre Porto

“The DNA profile from this item is at least 510 nonillion times more likely if it originated from John O'Keefe and two unknown individuals than if it originated from three unknown, unrelated individuals. And this provides support for an inclusion.”

Porto gave the reported comparison result for the passenger-side-taillight sample.

“Yes. So that testing began the same as the four-step process. I would extract the hair and then went to quantitation. After quantitation, I determined that there was no human DNA detected. So then testing was halted at that step.”

Porto described the limit of the laboratory's testing of the hair sample.

“So transfer DNA just means DNA that sort of transfers based on just some activity that could happen. Like if somebody touches a water bottle, they might transfer some DNA onto that water bottle.”

Porto explained the concept of transfer DNA before stating that he could not determine how or when DNA was deposited.

“Yes. So during our validations, we only validated mixtures up to four contributors because we determined that once you get more than four, at least five contributors into a mixture, it becomes too complex to be able to make any reliable comparisons to that mixture.”

Porto explained a laboratory limitation on interpreting complex DNA mixtures.

“The DNA profile from this item is at least 510 nonillion times more likely if it originated from John O'Keefe and two unknown individuals than if it originated from three unknown unrelated individuals. This provides support for an inclusion.”

Three-contributor passenger-side tail-light DNA-profile result supporting an inclusion of O'Keefe at the stated likelihood ratio

“So there was no human DNA detected and STR analysis was not performed.”

Hair from the vehicle's exterior passenger-side rear handle yielded no usable DNA, requiring mitochondrial testing at an external lab

“The DNA profile from this item is at least 530 nonillion times more likely if it originated from John O'Keefe and two unknown individuals than if it originated from three unknown unrelated individuals. This supports an inclusion.”

DNA finding on the broken drinking glass exterior from 34 Fairview Road

“So I determined that there were five contributors, so that makes it too complex for us to do comparisons to it.”

One evidence item (sneaker stain) was too complex for comparison, illustrating the limits of the lab's validated protocols

“No, I'm not.”

Porto said he could not determine when the DNA was deposited on the passenger-side tail light.

“Based on our protocols, we're not able to do any comparisons to any mixtures that are five or more contributors. So it's not suitable for comparisons.”

Porto said the sneaker mixture had five or more contributors and was too complex for comparison under the laboratory's protocols.

“That depends. It can happen, but it's possible. Yes.”

Porto's qualified testimony was that multiple DNA contributors on clothing can happen depending on the circumstances, and he would not call that a complete anomaly.

“The DNA profile from this item is 510 nonillion times more likely to have originated from John O'Keefe and two unknown individuals than if it originated from three unknown unrelated individuals.”

Reiterates the overwhelming statistical match of O'Keefe's DNA on the tail light.

“Correct. They were interpreted as originated from a single contributor.”

Confirms the 13 specified stain profiles on O'Keefe's shirts were interpreted as single-contributor DNA; this conclusion does not extend to other clothing samples addressed on cross.