EDMONTON

For likely the first time ever in a Canadian courtroom, an Edmonton jury was shown actual preserved body tissue from an alleged homicide victim on Friday.

While testifying at the first-degree murder trial of Brad Barton, medical examiner Dr. Graeme Dowling explained his belief of what happened while using the victim's preserved pelvic area, which was removed at autopsy.

Prior to Dowling taking the witness stand, the judge in the case warned jurors that it would be a "difficult" day and they would be shown photos and tissue of the victim.

"It is graphic and it is upsetting," said Court of Queen's Bench Justice Rob Graesser, adding it needed to be done.

Dowling also apologized to the jury, describing the evidence as "disturbing," but important.

Barton, 46, is accused of the June 22, 2011, slaying of sex trade worker Cindy Gladue, 36, and the Crown is alleging he fatally stabbed her in the vagina.

Dowling testified Gladue died from massive blood loss caused by a "perforating sharp injury of the vagina wall."

He then used both autopsy photos and the victim's preserved pelvic area, which were shown on a giant screen in the courtroom, to illustrate the fatal 11-cm cut.

The pathologist told jurors that it is his belief that the cut was caused by a sharp object, such as a knife, as the edges of the lethal injury were "clear" and there was no evidence of bruising or scraping at the site, which he said would be more consistent with a blunt force trauma.

Dowling also testified that, while it would not take much force to cause the injury through the vagina wall, it would take "considerable" force to do it with blunt force.

He denied hypothetical suggestions from the Crown that the injury involved could have been caused by fisting, unless there was "extreme" or "excessive" force used, and said that would lead to a tear rather than a cut.

Under cross examination, Dowling agreed it was a "very unusual" wound and said he had never before dealt with a case involving a vaginal cut leading to a fatal blood loss.

He also conceded he "could be wrong" in his belief that the injury was caused by a sharp-edged instrument as opposed to by blunt force trauma.

As well, he conceded that a fingernail, if very thin and exceptionally sharp, could cause a cut, although he said nails would typically cause blunt trauma like a scratch.

Defence lawyer Dino Bottos asked Dowling many questions about the rare sexual practice of fisting.

Earlier in the trial, the jury heard a dramatic 911 call in which Barton, an Ontario trucker, revealed he had found a woman in his hotel tub "covered in blood."

In the 8 a.m. June 22, 2011, call, Barton is asked by the 911 operator what his emergency is.

"It's a long story," replied Barton. "I woke up. There's a girl in my bathroom frigging covered in blood."

The jury has also seen video showing Barton and Gladue together at the Yellowhead Motor Inn.