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The Tori Stafford murder trial resumed on Friday with testimony from the Ontario police detective who found the eight-year-old girl's body.

Det. Sgt. Jim Smyth took the stand in the murder trial of Michael Rafferty, Friday morning and discussed his role in the case.

Smyth was the officer who discovered Stafford's body on July 21, 2009, after an extensive police search, in a field near Mount Forest, north of Guelph. He later interrogated Rafferty's then-girlfriend Terri-Lynne McClintic.

At the time of the discovery, Smyth refused to say what led him to the remains.

"I was driving through an area to assess that area to see if it was somewhere we wanted to search," he said at the time in an interview with CP24.

"We had certain information to assist us with our search."

On Friday, some of that information was finally revealed in court.

Smyth testified that a transmission from Rafferty's phone on the night Tori went missing was traced to a cellphone tower near the rural area.

Smyth told the court that he decided on a hunch to go to the area alone on a Sunday.

That's when he spotted something familiar from earlier interviews with McClintic, who had implicated herself and offered to help find Tori's body.

McClintic had drawn images from the area and gave police directions, both of which were used in the search.

Smyth testified that McClintic was interrogated several times over the course of the investigation.

And by using her sketches, he was able to find the body when police drove to the scene.

"I could see a portion of a garbage bag underneath the rocks," Smyth testified.

He took long pauses during his testimony and required time to compose himself.

"I moved one rock aside. I touched the bag because I didn't know if it was a piece of scrap."

Inside the bag was Tori's remains, he told the court.

"It took a moment to sink in. Once I gathered my thoughts, I stepped back I looked around and I tried to assess ‘what is our crime scene, here.'"

McClintic, 21, pleaded guilty to Tori's murder in April 2010 and was sentenced to life in prison.

Rafferty, 31, has pleaded not guilty to first-degree murder, sexual assault causing bodily harm and kidnapping.

Tori was abducted outside her Woodstock, Ont. school on April 8, 2009. Her partially-clothed body was found in the rural area 103 days later.

Smyth joined the investigation nine days later and, on May 19, 2010, held his first interview with McClintic.

The court was showed photos of the area, and the judge asked the jury to remain clinical throughout the disturbing testimony.

"I simply ask you to do your best to establish an attitude of sort of clinical detachment," Superior Court Judge Thomas Heeney said. "I know it's easier said than done. I simply ask you to do your best."

A video of McClintic's interview with police from May 24, 2009 was submitted into evidence in Rafferty's trial. In the video, McClintic tells Smyth that it was Rafferty who killed Tori by hitting her several times with a hammer.

McClintic gave a different version of events when she was called to the stand, claiming that it was her, not her former lover, who delivered the fatal blows.

Smyth's testimony is expected to stretch through Friday and into next week.

Smyth is the same interrogator who got convicted sex killer Russell Williams to confess to the murder of two young women while he was the commander of CFB Trenton.

With files from The Canadian Press