The investigation into Dylan Redwine’s death has stretched on for so long, that Friday’s testimony in the trial for the boy’s father, Mark Redwine, resembled a history class focusing on the advancements made in DNA science since June 2012.

Mark Redwine, 59, is charged with second-degree murder and child abuse resulting in Dylan’s death during a custodial parenting visit for the then 13-year-old during the Thanksgiving holiday in 2012.

Prosecutors say Redwine, enraged by sordid photos Dylan had discovered that showed him in women’s clothing and a diaper and eating feces from a diaper, killed Dylan late on the night of Nov. 18.

Redwine has pleaded not guilty.

Redwine has said he woke early on Nov. 19, assumed Dylan was sleeping in and ran errands in town. After coming back in the afternoon, he realized Dylan was missing.

Defense attorneys in opening arguments said Dylan left the house early and was likely killed by a bear or a mountain lion in the remote area around Redwine’s home at the north end of Vallecito Reservoir.

Analyses of DNA evidence are focusing on samples not only from Dylan and Mark Redwine, but also Dylan’s older brother, Cory; his mother, Elaine Hall; and Mark Redwine’s half-brother, David Stone.

A new software program, STRmix, was adopted by the Colorado Bureau of Investigation in 2018, and evidence in Dylan’s death was retested using the software. It was the first evidence from a criminal case in Colorado tested using STRmix, said Sarah Miller, who until recently was program manager of the Colorado Bureau of Investigation Forensic Lab.

Miller now works for a private DNA laboratory in Florida.

Miller testified that DNA collected on a coffee table in Mark Redwine’s Vallecito home had overwhelming statistical probability of coming from two individuals – Dylan and Mark Redwine.

But DNA tests have their limits, Miller told defense lawyer Justin Bogan during cross-examination.

“STRmix can’t tell you when the DNA was deposited, and it can’t tell you how it was contributed, whether it was blood, saliva, semen or skin,” Miller testified.

Miller told Bogan that further analysis showed 84% of the DNA sample from the coffee table came from Mark Redwine and 16% came from Dylan Redwine.

All the tests conducted were from minute samples collected using chemical techniques to find the presence of blood that can’t be seen by the naked eye.

The first of several rounds of samples were obtained from Mark Redwine’s house 10 days after Nov. 19, 2012 – the date Dylan was reported missing by his father.

It is hard to interpret the percentage of DNA from various contributors from a DNA sample, Miller said on the stand.

The contribution of DNA to a sample, she said, could depend on if one person was at the site of its collection more frequently than the other person.

“The more likely you sit in that chair the more likely we’ll find DNA in your chair,” Miller said in response to a question asked by a juror.

The amount of DNA collected at a site also could be degraded by cleaning, by the length of time it had been deposited, by bacteria, ultraviolet light and a host of other factors, she said.

In addition, blood, semen and saliva would have left behind more DNA than skin, sweat or hair cells, she said.

Rebecca Strub, who first analyzed DNA in the case back in late 2013 and early 2014 when she was working at a CBI forensic lab in Pueblo, also testified Friday.

Strub’s testing was the first to confirm bones found along Middle Mountain Road in June 2013 were DNA matches to Dylan.

Strub also conducted DNA tests on dozens of items collected in October 2013 at Mark Redwine’s Vallecito house, including a shoe, shirts, pants, shoelaces and underwear.

The October 2013 collection of items for DNA testing also included dozens of household items, such as fireplace tools, a tire iron, a duffel bag, speakers, a kitchen table rug and the wooden front door threshold.

The tests all came back negative except for a partial DNA profile of Dylan on a pair of Dylan’s underwear, Strub said.

Strub’s DNA analysis of the coffee table, indicated there was strong support that both Mark Redwine and Dylan contributed DNA to the coffee table sample.

Her analysis also showed that DNA from Hall, Stone and Cory Redwine all could be excluded from the coffee table sample.

Strub said when she conducted her DNA analyses, they looked at 16 different areas of the DNA strands located in every human cell. Now, tests like STRmix are looking at 24 different spots on DNA strands that are located in the nucleus of the cell.

Strub concurred that DNA analyses have limitations – as Miller also pointed out.

“I can tell you whose DNA profile is in a sample. I can’t tell you how or when it got there,” she said.

Strub said Dylan’s DNA could not be excluded from a number of positive tests in Mark Redwine’s living room, including a love seat cushion, a couch cushion, the floor in front of the love seat, the coffee table and the floor under a rug beneath the coffee table.

When prosecutor Michael Dougherty asked Strub if the inability to exclude Dylan’s blood from multiple positive tests in the living room meant it was likely Dylan bled in the living room in multiple places, she offered a simple answer: “That is correct.”

parmijo@durangoherald.com

An earlier version of this story erred in reporting Dylan Redwine’s DNA was found on Mark Redwine’s underwear. The boy’s DNA was found on his own underwear.