A jury saw glimpses Wednesday of two strikingly different Terri-Lynne McClintics: one, the weeping teen who claims she unwittingly led Victoria Stafford to her death and the other, a hardened young criminal who talked of smashing skulls, torturing victims and killing witnesses.

WARNING: Graphic details from this court case may disturb some readers.

The woman who confessed to murder in the death of the Grade 3 student gave a tearful videotaped confession to police weeks after Tori disappeared in April 2009, which court watched Wednesday, but a year earlier while in a detention centre she wrote about pent-up rage driving a desire to murder random people.

"I juz wanna be on road n take the first person I see, grab em...bring em wit me (and)...mutilate the (expletive) out of them, smash (their) skull apart then piece it togetha like a puzzle that way (they) stay conscious of the pain I'm inflictin on em," McClintic wrote to a friend while in custody in March 2008.

She was doing time for robbing and stabbing two people, court heard, and it was a breach of probation for that offence that led her into custody after Tori disappeared April 8, 2009. Some initial tips named McClintic as a suspect and she was arrested April 12 on the probation violation, though it was not until May 19 that she confessed to Tori's murder.

A police video from McClintic's full confession a few days later, with a sobbing 18-year-old McClintic saying she stood watching, frozen as her boyfriend Michael Rafferty raped and killed Tori was shown to the jury at Rafferty's first-degree murder trial Wednesday.

The jury was shown excerpts of McClintic's police interview earlier, but at the time Superior Court Judge Thomas Heeney told them they couldn't use it as evidence in the trial, only to assess McClintic's credibility.

Her story has markedly changed since that interview. McClintic now says she was the one who wielded the hammer, snapping due to childhood trauma after witnessing the alleged sex assault.

Heeney told the jury Wednesday that he made a ruling that the video statement falls under an exception to the traditional rule about prior inconsistent statements, and they can now consider it as evidence in finding the facts of the case. Jurors will still have to assess McClintic's credibility on the video, just as they have to assess her credibility on the stand, Heeney said.

McClintic, 21, is already serving a life sentence after pleading guilty to first-degree murder in Tori's death and is now testifying as a witness at Rafferty's trial.

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

After the video was played Rafferty's lawyer, Dirk Derstine, began cross-examining her, and showed a long series of letters she wrote while in custody before the killing. They are filled with gory, violent imagery, talk of wanting to go on a "killing spree" and Crips gang symbols. They paint a picture of someone who had built a reputation in custody as a tough, violent person, who bragged that even the guards were afraid of her, court heard.

In the letter in which McClintic talks about wanting to smash someone's skull, she describes ways in which she would torture her victim, including lighting them on fire.

"Sweep up the ashes when the flames die then keep up (and) the next (person) I don't like iz gonna drink them ashes," McClintic wrote.

In that letter she also talked about dyeing her hair so she wouldn't be recognized. When she was arrested, a box of hair dye was found in her room. She has testified Rafferty bought it for her and urged her to use it after Tori's killing, but she didn't get a chance before her arrest.

"I feel like a vampire in heat," she wrote in another letter from the detention centre. "I'm so blood thirsty I just wanna be on road so I can take the first person I see (and) shatter their skull."

McClintic also talks, in several of the letters, of wanting to kill, torture or hurt people or their families, including a witness in a friend's case, someone who had mouthed off to her and the people she stabbed. For the latter she had tracked down their names, addresses and phone numbers, and agreed in court that it appeared she was sending this information in a letter so someone not in custody could hurt them, or worse.

"There seems to be a bit of a theme that you're bringing forward...not only will you do terrible things to people who make you angry, but you will do terrible things to innocent people attached to those people?" Derstine asked McClintic.

"I would agree that I had anger issues and I did seek out to hurt those that had done something to, as I had seen it, hurt or anger me in some form or another," McClintic said.

Court has heard McClintic abducted Tori outside her school, then the three drove in Rafferty's car to a rural area more than 100 kilometres north.

"I could hear her calling out for me saying, 'T, make him stop'," McClintic says on the video, describing how she walked away during the alleged sex assault. "I wanted to grab her, take her away from him, but I took a couple steps and felt like I walked into a brick wall."

There was a break at one point during the sexual assault when Tori needed to use the washroom, McClintic said, and she took Tori a few steps away from the car.

"With me, she was good," McClintic says in the interview. "She was great. She wasn't scared of me."

When Rafferty killed Tori, kicking her, stomping on her and hitting her in the head several times with a hammer, it seemed like "he knew what he was doing," McClintic tells Ontario Provincial Police Det. Sgt. Jim Smyth.

"I felt at the point of tears a lot, and I didn't want him to see that. I didn't want him to see any of that," she said.

Rafferty made her help put Tori's body into several layers of garbage bags, McClintic said, and Smyth asked how he got her to do those things.

"He said, 'You're in it just as far as I am,"' McClintic told him. She decided to tell police the story so Tori could be brought home, McClintic said in the interview. Tori's remains would be found in July, 103 days after she went missing, partially clothed and in garbage bags in a field and under a pile of rocks, court has heard.

As the video of the interview was played in court Wednesday, Rafferty sat in the prisoner's box shaking his head.

Smyth asks at the end of the interview if McClintic has left anything at all out of the story.

"No," she says. "No. Everything, I've thrown everything out, everything, like I've laid it all out. That's it."