Los Angeles police are refusing to comment on a report that detectives are treating Michael Jackson's death as homicide after concluding that the singer was killed by a powerful anaesthetic.
The TMZ website, which broke the news of Jackson's death, cites multiple law enforcement sources as saying that the investigation is focusing on Dr Conrad Murray after evidence pointed to the anaesthesia Propofol as the cause of death. Investigators believe the drug, which is administered intravenously and is usually used only in hospitals in controlled conditions, was given to help Jackson sleep because he suffered from chronic insomnia.
Murray has said he found Jackson on the day he died and tried to revive him with CPR. His lawyers deny he "furnished or prescribed" Jackson with drugs.
TMZ quotes law enforcement sources as allegedly saying there is "plenty of powerful evidence" that Murray administered the drug to Jackson. The evidence includes an intravenous drip stand and an oxygen tank found in the star's home.
Police sources have told the US press that Murray is not co-operating with the investigation. He has been interviewed twice under caution, which led detectives to conduct a second search of Jackson's home, during which vials of Propofol were discovered.
Investigators' suspicions were also aroused by the delay in calling the emergency services after it was discovered that Murray waited up to 30 minutes.
Murray's lawyer would neither confirm nor deny that his client administered Propofol to Jackson. The police said there would be no public comment on the investigation until it was complete.