Source: Dr. injected Jackson before death

LOS ANGELES, July 27 (UPI) -- Michael Jackson's personal physician administered a strong drug investigators think killed the U.S. pop star, a source told CNN Monday.

Dr. Conrad Murray, a doctor hired by the company that was producing a series of Jackson concerts, was at the Los Angeles home where Jackson was staying when he died June 25. Citing a source close to the Jackson family that it said had knowledge of the investigation, CNN reported authorities Murray administered the drug to Jackson before the singer died.

Law enforcement sources said Sunday paramedics found Jackson dead when they arrived at his home June 25. The sources said paramedics wanted to pronounce Jackson dead but Murray had him transported to a hospital, TMZ.com reported Sunday.

An autopsy indicated Jackson had the powerful drug Propofol in his system, E! News reported last week, although the official cause of death was still under investigation. The drug is administered intravenously and puts people in a near-comatose state.

Police have not said who administered the Propofol to Jackson.

Police last week searched Murray's Houston office.