Michael Jackson was allegedly killed by an aide while his doctor slept.

However, Murray was asleep at the time so one of Michael's aides reportedly gave him a shot of powerful painkiller Demerol and the combination of the pain relief and Propofol - also known as Diprivan - is thought to have triggered a fatal heart attack.

An insider told Britain's The Sun newspaper: "Murray would set up a system to give Michael a steady intravenous release of Diprivan through the night.

"But this time Michael woke up before Murray did and asked one of his aides for some Demerol.

"The aide gave it to him, but it was too soon after receiving the anaesthetic. That's what killed him."

When Murray - who is being investigated for manslaughter - awoke he found the 50-year-old star had stopped breathing and desperately tried to revive him.

Murray is said to have confessed to Los Angeles police about administering Propofol - which should only be given in a hospital environment - two days after Michael died.

However, his lawyer has always insisted Murray denies giving the 'Thriller' singer anything that killed him.

Michael is thought to have first taken Demerol in 1984 to help ease the pain of the burnt scalp he suffered while filming a Pepsi TV commercial.

Meanwhile, Michael's sister La Toya believes her brother is performing for the angels in heaven.

Writing on her blog, she said: "Michael, after 50 years of waiting, God has finally called you home to do what you do best.

"He shared your extraordinary talent with us all for many decades and now it's time for you to spread your wings to a much higher level, which of course I know you will do, and join the other angels and give them an incredible eternal performance."