When Montreal-born author Ian Halperin first set out to write the definitive Michael Jackson biography, his intention was to nail the pop icon to the wall.

It was 2005 and Jackson had just been acquitted of a second charge of child molestation.

By the time Halperin, 44, finished the book, and long before Jackson died two weeks ago, his opinion of the troubled artist had undergone a 180-degree shift.

"I interviewed all kinds of people connected to the case and kids who stayed at NeverLand, and my final conclusion today is that he is 100 per cent not a child molester," Halperin said in an exclusive interview with The Gazette this week.

Rather it was Jackson's childlike attitude toward both his business dealings and his personal life that were his undoing, Halperin said.

As fate would have it, Halperin's book was ready to go to the presses one day before Jackson died on June 25.

After some furious rewrites and a change of title, Unmasked: The Final Years of Michael Jackson will hit bookstores on Tuesday.

Halperin, who worked briefly in The Gazette library in 1986, decided to give the first Canadian print interview to this paper before the publication of what will undoubtedly be a bestseller.

He declined to say what he stands to make on the sales of this book, which will initially be sold in Canada, the U.S., Britain and France.

"At this point, I've been working 24/7 on finding out more information on how he died. I've poured blood, sweat and tears into this story for so many years, the last thing I want to come out with now is how much I'm going make on this; it's ridiculous," he said.

Halperin is on the record in December as predicting the King of Pop's death, missing the date by one day.

"People were skeptical when you say someone has six months to live and I said that Dec. 24, 2008," Halperin said from Los Angeles the day after a massive memorial service at the Staples Centre.

"I've spent years researching this, getting access to a lot of his confidential records and documents, and he really was a candidate to pop off at any second.

"He hasn't been in great shape for a long time, both mentally and physically, so I wasn't just saying something off the top of my head. I was serious." Halperin used many methods to infiltrate the Jackson camp for the unauthorized biography. He befriended numerous people in Jackson's inner circle and went undercover as a hairdresser, taking a two-month course learning how to style hair.

"Sources that were close to him helped me out. ... They were concerned about a lot of the vultures in his camp, so they'd give me tips," he said. "No one really refused to speak to me." Halperin cites several pivotal events in Jackson's life that led to his downward spiral: his addiction to prescription painkillers after suffering burns in an accident while filming a Pepsi commercial in 1984; his first charge of child molestation that surfaced in 1993; the court case based on more charges in 2004; and the prospect of a 50-concert tour at the age of 50.

He quotes a letter he says he dug up from Jackson's insurance company demanding the pop star settle the 1993 charges levied by the family of Jordan Chandler.

"Michael was livid, he broke down in tears, he did not want to settle, he wanted to prove his innocence." Halperin says in his book that the second boy to accuse Jackson of sexual touching was drugged when he made his statement.

"Well, his dad was a dentist, but I don't want to go into too much detail because it's all in the book and I don't think the publisher will be too happy," he said.

He also accuses the family of the second boy, Gavin Arvizo, of "having a history of being fraudsters; they had tried this drill before on other people." In the first case, it is rumoured that Jackson paid $25 million in 1994 to the family of the first boy. The second case, which went to court, ended in acquittal in 2005.

"The child-molestation charges just drained him, in legal fees and also mentally. In the second case, he didn't want to go through it again, and that's why he became addicted to drugs and alcohol and had to go through rehab several times," Halperin said.

"When he agreed to do the 10 concerts in London, he was cool with that, but not the 50 (concerts) that were forced on him by his handlers who were drooling at the prospect of all that money.

"They never cared about him and just wanted to see what he could do for their own bank accounts." Halperin was so sure Jackson would never sing a note or bust a dance move in London that he never bothered to book plane tickets.

Halperin echoed what many people have said since Jackson went into cardiac arrest in a rented Hollywood mansion - that drugs killed the entertainer. The autopsy results, particularly the toxicology report, have yet to be released.

"Well, look, definitely prescription drugs were involved, that's no secret, obviously, but I don't think you have to look at the autopsy to find out what killed him.

"You just gotta go to the money and it was greed that killed Michael Jackson. ... People took advantage - and I allude to the last 15 years - of his naïveté as an excuse to cash in, and that's the real tragedy and that's what drove his physical and mental pain.

"He has been the victim of extortionists, people who have come after him maliciously, and it's very sad. That's what led to the emotional pain and that's what drove him to numb himself." Halperin also says Jackson wasn't sober when he sat for a damming interview with British journalist Martin Bashir in 2003 and that Jackson's marriage to Debbie Rowe broke up because she was unable to bear any more children after she gave birth to Paris.

Other tidbits from the book? "I think people will be surprised to see the role the Church of Scientology (played) in Michael's marriage to Lisa Marie (Presley), who was a devout Scientologist," Halperin said.

He also said he goes into detail about the biological origins of Jackson's children.

"I feel extremely bad for the kids, because Michael was such a doting father and especially at the end, he just lived for his kids."