Jackson's logistics director Alberto Alvarez reportedly told investigators that Jackson's mouth and eyes were open and he could not see signs of life when he came into the pop star's bedroom. Murray was working frantically to try to resuscitate Jackson.
"He had a reaction, he had a bad reaction," Murray told Alvarez, according to the report.
Alvarez said Murray then filled a bag with sedatives before telling him to call 911.
The report also revealed that Jackson's children, Paris and Prince, came into the room and cried before a nanny ushered them out.
Murray's lawyer, Ed Chernoff, rejected the accusation that Murray was covering up anything.
"He didn't say any of those things. Then two months later, all of a sudden, the doc is throwing bottles into the bag," Chernoff told The Associated Press. "Alvarez's statement is inconsistent with his previous statement. We will deal with that at trial."
Murray pleaded not guilty to involuntary manslaughter last month. Los Angeles prosecutors charged the Houston-based cardiologist with allegedly administering a lethal cocktail of painkillers and anesthetics to the entertainer hours before he died June 25.
Involuntary manslaughter carries the shortest sentence of any homicide charge in California. If convicted, Murray faces up to four years in prison.
Alvarez's report could be a strong blow to Murray's defense, according to legal expert Dana Cole.
"If he was in a sense cleaning up the room so that the paramedics wouldn't know in fact [what] he gave to Michael Jackson, that is a problem," Cole said.
An investigator's narrative released in February by the L.A. County's coroner's office included details of the June evening Jackson's body was found. Jackson's bedroom is described as outfitted with the usual furnishings: a queen-size bed, chairs, a dresser and a television.
There was also "a green oxygen tank" beside the bed and bottles of prescription medication scattered over several tables, along with medical supplies, such as latex gloves, a box of catheters, disposable needles and alcohol pads.
The 51-page coroner's report also described Jackson's vitiligo, the pigmentation-lightening disease the singer was said to have. His skin had "patches of light and dark pigmented area. His hair "was sparse" and woven into a wig. His lips and eyebrows had been permanently tattooed.
The autopsy report concludes that "the cause of death is acute propofol intoxication" and that "the standard care for administering propofol was not met ... Recommended equipment for patient monitoring, precision dosing, and resuscitation were not present."
Following an autopsy and the release of a much-anticipated toxicology report last fall, investigators concluded that Murray administered to Jackson, 50, the powerful anesthetic propofol and a mixture of other sedatives that led to his death.
"Murray did unlawfully, and without malice, kill Michael Joseph Jackson ... in the commission of an unlawful act, not amounting to a felony; and in the commission of a lawful act, which might have produced death, in an unlawful manner, and without due caution and circumspection," prosecutors said in a statement.
Murray was hired to accompany Jackson for a scheduled series of concerts to be held in London last summer. Jackson died weeks before the tour was to begin.
Murray has denied any criminal wrongdoing.