Michael Jackson performs during the halftime show at the Super Bowl XXVII in Pasadena, Calif., on Jan. 31, 1993.
LOS ANGELES (CBS/AP) The investigation into Michael Jackson's death seems to be tightening further around the pop star's personal physician, Doctor Conrad Murray.
A law enforcement official told the Associated Press that Jackson's personal doctor gave him a powerful anesthetic through an intravenous drip to help him sleep, and authorities believe the drug caused the pop singer's death.
The official, who spoke on condition of anonymity because the investigation is ongoing, said Jackson regularly received the anesthetic propofol and relied on it like an alarm clock. A doctor reportedly would administer it when Jackson went to sleep, then stop the IV drip when the singer wanted to wake up.
On June 25, the day Jackson died, Dr. Conrad Murray gave him the drug through an IV sometime after midnight, the official said.
Murray's lawyer, Edward Chernoff, has said the doctor "didn't prescribe or administer anything that should have killed Michael Jackson." When asked Monday about the law enforcement official's statements he said: "We will not be commenting on rumors, innuendo or unnamed sources."
In a more detailed statement posted online late Monday, Chernoff added that "things tend to shake out when all the facts are made known, and I'm sure that will happen here as well."
Toxicology reports are still pending, but investigators are working under the theory that propofol caused Jackson's heart to stop, the official said. Jackson is believed to have been using the drug for about two years, and investigators are trying to determine how many other doctors administered it, the official said.
Using propofol to sleep exceeds the drug's intended purpose. The drug can depress breathing and lower heart rates and blood pressure. Because of the risks, propofol is supposed to be administered only in medical settings by trained personnel.
Murray, 51, has been identified in court papers as the subject of a manslaughter investigation, and authorities last week raided his office and a storage unit in Houston. Police say Murray is cooperating and have not labeled him a suspect.
PREVIOUSLY ON CRIMESIDER
July 22, 2009 - Feds Raid Jackson Doctor's Clinic
July 10, 2009 - Police Haven't Ruled Out Homicide In Michael Jackson Case
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