Only a tiny chance DNA found at mail bomb scene isn't Guido Amsel's: RCMP analyst

The trial of accused mail bomber Guido Amsel took a deep dive into DNA science Tuesday, hearing evidence that allegedly linked him to explosions in 2013 and 2015.

RCMP DNA analyst Christopher Lett said a known blood sample previously identified in court as belonging to Amsel was compared to a mixed DNA profile developed from a plastic pouch found at the scene of the bombing that seriously injured lawyer Maria Mitousisin July 2015.

The mixed DNA profile was determined to include the DNA of Mitousis and Amsel as "possible contributors," Lett said.

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When Lett isolated the two contributors, the"possible" Amsel sample and the known Amsel sample were found to be a positive match, with just a 1 in 1.2 quintillion chance they came from different people.

"It was almost like receiving another single source profile after I removed [Mitousis] from the mixture," Lett said.

Amsel, 51, is charged with five counts of attempted murder, one count of aggravated assault and several explosives offences in connection with three mail bombs delivered to his ex-wife, Iris Amsel, and two law firms in July 2015, and a December 2013 explosion outside Iris Amsel's Rural Municipality of St. Clements home.

A DNA profile developed from a piece of string found outside Iris Amsel's home following the 2013 explosion was also found to be a match for a known Guido Amsel profile, with a 1 in 2.6 quintillion chance they came from different people, Lett said.

Lett said ultraviolet rays, moisture and humidity degrade DNA over time, suggesting the DNA had been transferred to the string a relatively short time before it was seized by police.

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"There are studies that show blood [a major source of DNA] deposited on the outside of a window will be undetected in a number of weeks," Lett said.

Defence lawyer Saheel Zaman argued the string could have been dislodged from an area where it had been insulated for years by forces that would degrade its DNA.

"Your inference is correct, there is a possibility there," Lett conceded.

Zaman said police can't tell how long DNA has been present in a location or whose DNA was deposited first in cases of multiple profiles.

"You would agree that the presence of DNA doesn't prove someone committed a crime?" Zaman said.

"That's correct, it doesn't prove the act," Lett replied.