WASHINGTON - Michael Jackson’s physician left him alone after putting him to sleep with a powerful anaesthetic in order to make telephone calls to family and friends, the Los Angeles Times reported Friday.

The Times quoted three people familiar with the investigation as sources for the report.

The cardiologist, Conrad Murray, is being investigated on possible involuntary manslaughter charges for his alleged administration to Jackson of Propofol, a drug normally only administered intravenously in surgical operating rooms in hospital settings.

Patients who receive Propofol normally are monitored for heart and breathing rate under the watchful eye of an anaesthesiologist.

After administering the drug June 25, Murray left the pop singer alone to make an unclear number of phone calls. When he went back to Jackson, he found the singer had stopped breathing.

Murray reportedly admitted to investigators two days after Jackson’s death that he had administered the drug, the sources told the Los Angeles Times.

Murry told detectives that Jackson had been using Propofol to help him sleep for over the past decade, and that the 50-year-old singer had never had problems with it in the past, so he felt ok leaving him alone.

Jackson employed Murray for $150,000 a month. Murray’s home and practice in Las Vegas have been searched by investigators for a record of his drug-prescribing practices.

After finding Jackson was not breathing, Murray tried to resuscitate him while someone else at Jackson’s Los Angeles rented home called the 911 rescue squad. The singer was pronounced dead at hospital.

The final results of Jackson’s autopsy have not yet been released, and investigators are also pursuing other physicians connected to Jackson’s care, the Times reported.