LAS VEGAS (AP) – Federal agents searched the home and office of Michael Jackson’s personal physician Tuesday in a widening investigation of whether administering a powerful anesthetic as a sleep aid was so reckless that it constitutes manslaughter.

Such charges against a doctor for the death of a patient would be extremely rare. Authorities would have to show there was a reckless action that created a risk of death.

After a three hour-search of Dr. Conrad Murray’s sprawling home near the 18th hole of a golf course in a private gated community, Los Angeles police and federal Drug Enforcement Administration agents carried away five or six plastic storage containers and several thick manila envelopes.

Across town authorities searched Murray’s medical offices, Global Cardiovascular Associates Inc., for nine hours seeking documents. Investigators removed several boxes but declined to describe what they had seized.

Murray’s lawyer, Edward Chernoff, issued a statement saying the sealed search warrant “authorized investigators to look for medical records relating to Michael Jackson and all of his reported aliases.”

Murray was present during the search of his home and assisted the officers, who seized cell phones and a computer hard drive, Chernoff said.

Though authorities characterize Murray as the target of the investigation, they have stopped short of labeling him a suspect.

Murray told investigators he administered the anesthetic propofol to Jackson the night he died to help him sleep, according to a law enforcement official who spoke to The Associated Press on condition of anonymity because the investigation is ongoing. The official told AP that Murray left the bedroom where Jackson was sedated and returned to find the star not breathing. It’s unclear how long Murray was out of the room.

The official said investigators are working under the theory that propofol caused Jackson’s heart to stop. Toxicology reports that should show what killed Jackson are expected as early as this week.

Propofol typically is used to render patients unconscious for surgery. The drug can depress breathing and lower heart rates and blood pressure.

Home use of propofol is virtually unheard of, and if Murray left Jackson’s side he would have violated guidelines for the safe use of the drug drawn up by the American Society of Anesthesiologists.

Those rules say a physician “should be physically present throughout the sedation and remain immediately available until the patient is medically discharged from the post procedure recovery area.”

In considering a manslaughter charge against a doctor, a patient’s complicity in taking the risk could reduce the doctor’s culpability, said Harland Braun, a prominent Los Angeles defense attorney who has represented doctors in cases involving administering of drugs.

If a doctor is aware of the risk, there might also be an issue of whether the patient knows that risk and decided to take it.

Chernoff has said the doctor “didn’t prescribe or administer anything that should have killed Michael Jackson.” He declined interview requests Tuesday.

The search of Murray’s home and business involved members of the DEA’s Los Angeles Tactical Diversion Squad, agency spokesman Jose Martinez said. The team typically looks into cases involving legally prescribed drugs such as narcotic painkillers that are illegally sold or obtained by people not authorized to have them, such as “doctor shoppers” who get medications from several physicians so they can sell the drugs or feed their addiction.

The Las Vegas searches were the second time in less than a week that investigators targeted Murray’s property. Last week authorities searched his Houston clinic and a storage unit. Court records show they were seeking evidence of whether the doctor committed manslaughter.

Murray, 51, who is licensed in California, Nevada and Texas, became Jackson’s personal physician in May and was to accompany him to London for a series of concerts starting in July.

He was staying with Jackson in the entertainer’s rented Los Angeles mansion and, according to Chernoff, “happened to find” Jackson unconscious in his bedroom the morning of June 25. Murray tried to revive him by compressing his chest with one hand while supporting Jackson’s back with the other.

Jackson is believed to have been using propofol for about two years and investigators are trying to determine how many other doctors administered it. Murray told investigators he had given Jackson the drug several times before, the law enforcement official told AP.

As investigators try to untangle Jackson’s complex medical history they have interviewed at least six doctors who treated him and searched records for transactions involving aliases Jackson may have used to get drugs.

The official said Murray directed investigators to a closet in the room where Jackson slept. In it, they found enough propofol and sedatives to fill two gym bags. The room also contained an IV line and three tanks of oxygen, which would be needed for administration of propofol.