A judge in a triple murder trial in Calgary has advised the jury it does not have to look at autopsy photos, after a juror requested a break during detailed testimony of the victims' stab wounds.

The bloody bodies of the couple and their son, eight, were found in their Medicine Hat, Alta., home in April 2006. Their daughter's boyfriend at the time, Jeremy Steinke, 25, is charged with first-degree murder.

The father was stabbed 24 times in the face, neck, chest, stomach, back, groin and leg, and suffered numerous bruises and lacerations that were defensive in nature, medical examiner Dr. Craig Litwin told the jury in Calgary on Friday.

The mother was stabbed 12 times, including a 12-centimetre deep wound that pierced her heart, he said. The boy suffered five stab wounds, including a wide, deep slash across his neck.

Litwin was testifying Friday morning about the injuries that led to the father's death and describing corresponding autopsy photos when a male juror asked for a break.

He raised his hand and said, "May I be excused for a second?"

Justice Adele Kent granted the break and returned 10 minutes later, saying the jury was OK, but wanted to take the lunch break early.

Kent then asked Crown prosecutor Ramona Robins if the court had to look at all of the autopsy pictures, acknowledging that they were "difficult" to see.

After the lunch break, it was decided that the jury can refer to the medical examiner's written report and look at corresponding photos if they desire for future reference, rather than having to view each autopsy image during Litwin's testimony.

None of the jurors chose to look at the photos of the boy's injuries on Friday.

Messages reveal plot to kill

Earlier on Thursday, Sgt. Timothy Schottner, a computer forensics expert with the Medicine Hat police, testified about messages sent between Steinke and his girlfriend, then 12, before the slayings.

Using a warrant, he said he obtained 4,000 pages of messages sent between March 1 and April 24, 2006, from Nexopia, a social networking site popular with teens.

The messages include exchanges between "souleater," the user name used by Steinke, and "runawaydevil," the account used by his girlfriend.

In one message, souleater writes to runawaydevil: "I miss you more than killing people. Can we get together and kill people?"

In another exchange, runawaydevil writes about her parents who disapprove of her relationship with the much-older boyfriend: "I hate them. I have this plan. It begins with me killing them and ends with me living with you."

Souleater replies: "Well I love your plan but we need to get a little more creative with like details and stuff."

On the blog section of his Nexopia page, souleater also posts: "Their throats I want to slit. They shall pay for their insolence. There will be silence. Their blood will be payment."

More than 20 people are still scheduled to testify for the prosecution when the trial resumes on Monday. The Crown has not ruled out calling Steinke's former girlfriend, who is serving a 10-year sentence as a young offender, as a witness.

With files from Bryan Labby