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A video of Terri-Lynne McClintic's 2009 interview with police, in which she tearfully tells an OPP investigator it was her former boyfriend, Michael Rafferty, who killed eight-year-old Victoria Stafford, can now be considered as evidence in Rafferty's trial, a judge ruled Wednesday.

Jurors were previously shown the hour-long statement McClintic gave to police on May 24, 2009 only as background information.

But in an unusual ruling, Justice Thomas Heeney, told the jury Wednesday morning they can now consider McClintic's answers to police as evidence and weigh it against an entirely different story she told on the stand.

It was an important development in the high-profile trial, where Rafferty stands accused of kidnapping, sexually assaulting and killing the little girl, known as Tori.

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

While McClintic, the trial's star witness, initially told police it was Rafferty who delivered the fatal blows to Tori's head with a hammer, she gave a different version of events on the stand.

She surprised the courtroom last week by saying it was her, not her former lover, who killed Tori by hitting her head several times with a hammer.

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

Rafferty, 31, has pleaded not guilty.

In the videotape of OPP Det. Sgt. Jim Smyth's interrogation of McClintic, she is initially reluctant to discuss Tori's murder.

"I don't know why you don't want to tell me, OK, but you need to tell me the truth about where Tori ended up," Smyth tells McClintic at one point, leaning in close.

"I am, I am!" she says through sobs.

But Smyth keeps prodding.

"Just tell me what you saw," he says.

"I saw Mike kick her a couple times… like… a garbage bag over her head," McClintic says, lowering her head.

"How many times did he hit her with the hammer?"

"I specifically, think specifically, I only saw him hit her a couple of times," she says.

McClintic later tells Smyth how she and Rafferty hid the body under a pile of rocks. She also says Rafferty told her she's as guilty as he is.

Three years later, McClintic recanted that statement at Rafferty's trial, saying she didn't want to admit to herself that she was capable of murder.

The jury also heard Wednesday that McClintic wrote disturbing letters about wanting to kidnap and torture someone more than a year before Tori was killed.

The letters then-17-year-old McClintic penned while she was serving time in a youth jail for robbery and stabbing were submitted into evidence by Rafferty's defence lawyer.

In one of the letters, McClintic described herself as a "vampire in heat" who is lusting after blood, CTV's Austin Delaney reported.