LONDON, Ont. - A young woman convicted of first-degree murder in the death of eight-year-old Victoria Stafford will face another round of likely combative cross-examination Thursday.

Terri-Lynne McClintic, 21, is testifying at the trial of her ex-boyfriend, Michael Rafferty, 31, who has pleaded not guilty to first-degree murder, sexual assault causing bodily harm and kidnapping in the death.

The jury has watched a videotaped police interview in which McClintic describes how Rafferty allegedly raped then killed Tori using a hammer, but now she says she's the one who killed the girl.

Despite the recantation that Rafferty killed Tori, his lawyer Dirk Derstine began his cross-examination Wednesday of McClintic with some testy exchanges.

He showed the jury a series of letters McClintic wrote from a detention centre before the murder that use disturbing, violent imagery and portray herself as a ruthless thug at the institution.

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.