There’s a chance two DNA samples belonging to Lyle McCann and Travis Vader were both found on a hat, but it’s far from certain.
Court heard Friday afternoon from DNA analysis expert Vivian Mohrbutter, a reporting scientist at the RCMP’s forensic laboratory in Edmonton, who analyzed several samples collected from scenes related to the McCann investigation. Several over those items contain Vader’s DNA.
She said, citing her laboratory reports, that a hat belonging to Lyle McCann found in his vehicle had DNA from two people on it. The first person’s DNA matches that take from McCann’s sneaker, which is considered a “putative known sample” for him. There is a one-in-34-billion chance of a random Canadian Caucasian producing an identical result.
The second person’s DNA matches a known sample taken from Vader, but with less certainty. The chances of a random Canadian Caucasian producing an identical result in one in 140,000.
The difference, as explained by Mohrbutter Friday and previously by her colleague Vashni Skipper, has to do with the quality of DNA taken. Depending on the quality of the DNA, there may be fewer genetic regions from which to make comparisons to a known sample using laboratory tests.
Vader is accused of murdering Lyle and Marie McCann, who were last seen at a St. Albert gas bar filling up their motorhome July 3, 2010, before departing on a trip to the West Coast with a Hyundai Tucson SUV in tow. Their motorhome was found burning two days later and their bodies have not been recovered. The SUV was recovered two weeks later.
Mohrbutter also testified about results from a tissue found inside the McCanns’ SUV and a pair of track pants found at a camp site the Crown alleges was one of Vader’s hideouts while he was being hunted by police.
Samples taken from both those items match Vader’s known sample, with a one-in-three-trillion chance of getting a random match from the Canadian Caucasian population.
She also testified that blood samples found on several canned goods in the SUV match a sample taken from Marie McCann’s hairbrush, which is considered a putative known sample for her. The odds of a random match in this case is one in 4.6 trillion.
In his cross-examination, defence lawyer Brian Beresh questions Mohrbutter first about napkins found in the SUV, which contained DNA samples from an unidentified male, and pointed that male had never been identified. He has argued previously the RCMP had “tunnel vision” in this investigation, and never seriously considered suspects other than Vader.
He also, in several cases, picked apart individual analyses piece by piece, point to specific locations on one chart or another from Mohrbutter’s report, in a highly technical discussion.
Beresh also raised doubts about the analysis done on the baseball hat that contained possible matches to both Lyle McCann and Vader, and determined samples from that hat were actually sent to another lab for further analysis to yield those results.
During his cross-examination, he was assisted by DNA expert Dr. Randell Libby, whom the defence is expected to call as an expert witness later in the trial.
He was not able to conclude his cross-examination by the end of the day, and Mohrbutter is expected to return Monday afternoon to continue with her testimony.
The sixth week of Travis Vader’s murder trial got off to a slow start today, with no witnesses expected to testify until the afternoon.
The morning consisted solely of a discussion about an application made by Vader’s defence. Justice Denny Thomas ordered the contents of that hearing to be sealed and subject to a publication ban.