The findings were revealed on Monday, when a previously sealed search warrant which contained them was made public in Texas.
There were also reports that the LA coroner has ruled that Michael's death was homicide, which - under Californian law - means he was killed either accidentally or on purpose.
These claims, which come from unnamed police sources, have not been confirmed, however.
According to the affidavit the LA chief coroner "had reviewed the preliminary toxicology results and his preliminary assessment of Jackson's cause of death was due to lethal levels of propofol".
The documents state that Michael's physician Dr Murray told police he had been giving the Thriller singer propofol as part of treatment for insomnia.
He said he had been concerned the star was becoming addicted to the drug and had been trying to wean him off, using other drugs.
On the morning of Michael's June 25 death, Dr Murray said he gave the singer several drugs, starting with valium at 1.30am, an intravenous injection of lorazepam half an hour later and, when the singer was still awake at 3am, some midazolam.
After giving various drugs over the next few hours, Dr Murray told officers he finally gave in to his patient's repeated requests for propofol and administered 25 milligrams via an intravenous drip.
He returned from making phone calls to find Michael had stopped breathing, he said, and tried resuscitate him. Meanwhile one of the star's staff called for an ambulance.
Michael was taken to hospital, where he was later declared dead.