Law Enforcement Doesn't Believe Dr. Murray

Law enforcement sources tell TMZ the L.A. County Coroner and the LAPD are not buying Dr. Conrad Murray's story that he gave Michael Jackson a relatively low dosage of Propofol before he died.

Sources say the L.A. County Coroner has determined Michael Jackson died from a lethal level of Propofol. There were "traces" of other drugs in Jackson's system, but nothing that would have killed him.

According to the search warrant affidavit, during Dr. Murray's interview with LAPD detectives two days after Jackson died, he said he gave Jackson 25 milligrams of Propofol shortly before the singer stopped breathing. Dr. Murray also said he had been giving Jackson 50 milligrams of Propofol for the prior six weeks so Jackson could sleep, but he felt the singer may have been forming an addiction so he cut back.

Here's the reality. It takes approximately 400 milligrams of Propofol for someone of Jackson's body size to sleep 8 hours -- that's 16 times the amount Dr. Murray says he gave Jackson the day he died.

Our law enforcement sources simply do not believe that 25 milligrams would have in any way compromised Michael Jackson, especially since he had developed a tolerance to a much higher level.