Investigators remove a body from the Medicine Hat home where a couple and their eight-year-old son were found dead in April 2006. (CBC)

Crime scene photos introduced at a triple-murder trial in Calgary brought some jurors to tears on Wednesday.

Jeremy Steinke, 25, is charged with the first-degree murders of a couple and their eight-year-old son in their Medicine Hat home in April 2006. The Crown is trying to prove that Steinke killed his young girlfriend's family so they could run away together.

Sgt. Gerald Sadlemyer from the Medicine Hat police force's forensic unit described to the jury Wednesday the extensive evidence that took more than week to gather.

Of the 2,000 photos Sadlemyer took during the investigation, the jury began looking through a collection of about 200 images on Wednesday.

The most obviously emotional reactions came when the jury saw the photos of the boy, who was found in his blood-soaked bed with a deep, wide stab wound across his neck. Toys and clothes spattered with blood could be seen in the photos of his bedroom.

One juror winced as she examined one photo, and three others wiped away tears with tissues. A few other members were visibly pale.

Knives, parts of home covered in blood, court told

Steinke maintained the same posture he has held since the trial began, staring at the floor with his head bowed down.

Sadlemyer said he gathered evidence from four sites:

• The house where the bodies were found.
• The mobile home where Steinke lived with his mother.
• Steinke's truck.
• Another truck in which Steinke and his girlfriend, then 12, were found in Leader, Sask., a day after the killings.

The jury heard that police seized a number of exhibits from the second truck, including blood-stained clothing, three knives, and the purse and ID belonging to the girl's mother.

Processing the crime scene at the family's home took five days, he testified.

Sadlemyer said two kitchen knives, light switches, door knobs and carpets in the house were covered in blood.

Several officers, who were the first to respond, have already testified that they found two knives in the house and bloody handprints smeared on the walls.

The girl, who was found guilty last year of three counts of first-degree murder, is serving a maximum 10-year sentence for young offenders as part of a rarely used intensive rehabilitation program.

If convicted, Steinke faces a life sentence with a minimum of 25 years in prison.

With files from Bryan Labby, Scott Dippel