Defence suggests person whose DNA was found on B.C. girl may not have killed her

A defence lawyer at the Ibrahim Ali murder trial in B.C. Supreme Court has proposed a theory that the person whose DNA was found on the alleged murder victim may not be the one who killed the teenager.

Kevin McCullough has finished cross-examining forensic biologist Christine Crossman, focusing on the fact Ali's genetic profile only matched samples found in the victim's vaginal and anal areas.

McCullough questioned the decision by investigators not to test some evidence that may establish another suspect in the case, asking Crossman to confirm if she has an idea whether stains found on the girl's clothing contained DNA.

The body of the 13-year-old girl, who can't be named because of a publication ban, was found in Central Park in Burnaby, B.C., in July 2017.

McCullough asked Crossman if she or the police noted that it was important to establish beyond a reasonable doubt the time of death and the time of sexual contact in this case, to which Crossman replied that DNA evidence can't be used to establish such timelines.

Crown prosecutors said earlier in the trial that evidence would show that Ali sexually assaulted the girl in a random killing.

Ali has pleaded not guilty to first-degree murder.