The Conrad Murray verdict was handed down a week ago (Nov. 7), with the doctor being found guilty of involuntary manslaughter in the case of Michael Jackson. Murray came under fire for administering the surgical anesthetic propofol to the singer outside of the operating room, which killed him.

Now, Frank Cascio, who was once the King of Pop’s personal assistant and manager, has written a tell-all book that makes the blockbuster claim that the singer began taking the dangerous drug as far back as 1999, well before he met and hired Dr. Murray.

According to the Associated Press (via TMZ), Cascio (who became a close friend of the late, great Jackson), wrote in his book, ‘My Friend Michael: An Ordinary Friendship With an Extraordinary Man,’ that Jackson began popping the pain killer Demerol in 1993 during his ‘Dangerous’ tour. The singer was introduced to the drug after he was famously burned while shooting a Pepsi commercial in 1984.  The author then revealed that Jackson took propofol after a stage accident took place in Munich in 1999.

Cascio said that he tried to talk to the singer’s siblings about his drug problems in 2001, and they all tried to speak to Jackson, but he wasn’t hearing any of it and simply pushed them away. Cascio added that Jackson was on a quest for inner peace, but never achieved it. He died trying. That makes his story that much more tragic.

Jackson passed away in June 2009. His battles with addiction were documented throughout his career.