WASHINGTON - In the final day of testimony for Week 3 of the Mansion Murders trial, the jury received a science lesson about what DNA is, how it can be left on and collected from items, and how it's analyzed.
ATF forensic biologist Emily Head said that heat, like that from a house fire, can degrade DNA, but can't change it to appear to belong to someone else.
The ATF lab was given known DNA samples from Savvas Savopoulos, Amy Savopoulos, Philip Savopoulos, Vera Figueroa, Katerina Savopoulos, Abigail Savopoulos, Nellie Gutierrez, Daron Wint, Derrell Wint, Jordan Wallace, and the Domino's delivery driver and Domino's supervisor.
DNA profiles of ATF staff and investigators at the scene were also available for comparison.
Of the 175 items that were submitted to the lab for analysis, many did not have results. But the ones that did were matches for Daron Wint, according to experts. His DNA was detected on the handle of a kitchen knife that was found propping open a basement window of the home, prosecutors stated. The probability that it would be someone other than Daron Wint's was 1 in 10 billion, according to officials.
DNA matching Daron Wint was detected on the neck and tag area of a green construction vest found in Amy Savopolous' burned Porsche, prosecutors said. According to officials, Daron Wint's DNA was mixed with DNA that matches Savvas Savopoulos.
Experts said the match probability on the samples found in the Porsche was 1 in 40 million and 1 in 10 million.
The jury then heard about DNA evidence on the infamous pizza crust. Officials said DNA matching Daron Wint was found in two spots. First, on an unchewed end of the crust, which they said the probability of a match was 1 in 10 quintillion. The end of that piece of crust had a bite taken out of it and experts said it returned DNA for a mix of two people.
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Head testified that Daron Wint's DNA was a "major contributor," again with a probability of 1 in 10 quintillion, while the other DNA sample was not suitable for comparison.
The jury was also shown pictures of the pizza boxes and the pizza crust. Both were found upstairs in the Savopoulos ' home.
Head said two DNA samples were located on a bloody baseball bat. One matched Amy Savopoulos, while the other was a match for Savvas Savopoulos, according to Head.
Philip Savopolous' DNA was detected on a leather strap hanging off the handle of a samurai sword, according to officials. No other DNA was on the sword. Prosecutor Christopher Bruckmann asked Head if a fire could degrade DNA. She said yes, and that she would not expect to see DNA on an item from a room that was engulfed in flames.
Vera Figueroa's DNA was detected near the knob and handle of a black baseball bat located in the family's living room, officials stated. What could be problematic for prosecutors was the finding of "accidental" DNA detected on other items.
DC Evidence Technician Officer Adrian Lancaster was involved in the collection of many items of evidence. His DNA was detected in swabs taken from the driver-door handle on the exterior of the red Mosler sports car, on blue cables that had been cut, and the top of a red gas can. Lancaster testified that when he was collecting the evidence, there was no electricity in the home and he was sweating.
Another ATF agent's DNA ended up on a pair of scissors that were hanging in a hallway closet. Steve Weitz, a supervisor at the ATF forensics lab, said he didn't touch the scissors and Head testified that his DNA could have accidentally transferred from a sneeze or a cough.
Head's own DNA was detected on a towel collected from the bathroom of Bedroom No. 2. Head testified that during sampling, the swab broke off. She, in accordance with accepted lab practice, then used the tip of the swab, and believes that the sleeve of her lab coat may have accidentally brushed the area that was sampled. Her DNA was mixed with another person's, but that other sample couldn't be identified.
During cross-examination, defense attorney Jeffrey Stein put the jury through a tedious discussion of DNA quantities, such as Head's DNA sample on the towel being one-half of a nanogram. Stein pointed out that the quantity of the DNA from Daron Wint on the kitchen knife was also less one-half of a nanogram.
Stein said there were five accidental transfers of DNA on items collected from the house and stated that Daron Wint's DNA on the handle of the kitchen knife was a microquantity. Head agreed that DNA can be transferred without skin contact, and that "there is no way to determine how, or when, DNA is transferred to an item."
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