Alex West, a reporter for the London-based Sun, interviewed Magnotta in December 2011 at a hotel room above a pub in Wembley over allegations the accused posted videos of cat killings.
Audio of the roughly 30-minute exchange between Magnotta and West, recorded surreptitiously by the journalist, was heard in court Wednesday.
It marked one of the first instances Magnotta has been heard speaking extensively as he has uttered few words since the beginning of his first-degree murder trial.
Two days after the interview with a "cocky" and "defensive" Magnotta, West and his employer received an email from a man they believed was Magnotta who suggested he was intending to kill a human and film the event in the near future.
"Next time you hear from me it will be in a movie I am producing, that will have some humans in it, not just pussys. :)," the author wrote near the end of the email, sent Dec. 10, 2011.
The email, which was rife with spelling and grammatical mistakes, was written under the name John Kilbride, but referenced a meeting with a "sexy" Sun journalist, leading the paper and West to believe Magnotta had authored it.
West, 33, testified that Kilbride was one of the young victims of convicted serial killers Ian Brady and Myra Hindley, perpetrators of the so-called Moors Murders in England in the mid-1960s.
He said the slayings are now part of "British criminal folklore."
"We believed this email to be from Mr. Magnotta," West said, adding officials at the paper alerted police.
West's testimony, given via video from the Canadian High Commission in London, is key as the Crown sets out to prove Magnotta's acts were planned and deliberate.
The Crown contends the accused was planning a murder up to six months in advance, as indicated in the email. Magnotta is charged with first-degree murder in Lin's slaying and dismemberment in May 2012.
Magnotta, 32, would be arrested and charged in June 2012 in connection in Lin's killing.
He has admitted the physical acts of which he's accused but has pleaded not guilty by way of mental disorder.
Magnotta faces four other charges: criminally harassing Prime Minister Stephen Harper and other members of Parliament; mailing obscene and indecent material; committing an indignity to a body; and publishing obscene materials.
West said he was following up on a tip sent to the news desk about Magnotta's whereabouts. He didn't know who Magnotta was at the time, but a quick look provided "a plethora of Internet hits based on simple searches for his name," he testified.
The newspaper had written about an anonymous kitten killer one year earlier.
During the interview on Dec. 8, 2011, Magnotta repeatedly denied having killed kittens and posting videos online. He also took offence with the suggestion by West he was trying to create a "cult of personality" online.
Magnotta also denied an Internet report he was dating convicted schoolgirl killer Karla Homolka, telling West simply that "I have nothing to do with her." He claimed he'd received 500 death threats in the past year alone and that police were aware.
Magnotta told West he wanted to be left in peace, was trying to live anonymously and denied sending anonymous emails to the newspaper.
"It's just one big frame job that I have to deal with after another," Magnotta said at one point. "I have nothing to do with this, I'm innocent."
West said no story was published based on the exchange.
Two days later, the email arrived, referencing a meeting with a journalist from the paper. Magnotta's name does not appear in the text.
The email writer assured the newspaper it would be hearing from him again in the near future, but warned "this time, however, the victims wont be small animals."
The author offered to send a copy of the next video and said: "You see, killing is different then smoking .. with smoking you can actually quit." The court heard the reference is believed to be attributed partly to a line from the 1992 movie "Basic Instinct."
Later in the message, he added: "Once you kill, and taste blood, its impossible to stop. The urge is just too strong not to continue."
It concluded: "Getting away with all this, now thats genius."
Quebec Superior Court Justice Guy Cournoyer told the jury the case is proceeding well and lawyers agreed to take a break Wednesday before the trial resumes Thursday.
The Crown could wrap up its case sometime next week, Cournoyer said.
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