LAS VEGAS — The potent anesthetic that Michael Jackson's doctor gave him as a sleep aid came from a Las Vegas pharmacy searched Tuesday by federal drug agents and police, a law enforcement official told The Associated Press.

Authorities are investigating Jackson's June 25 death as a manslaughter and believe the anesthetic propofol he was given at his rented Los Angeles mansion was a major factor. Propofol normally is used to render patients unconscious for medical procedures and only is supposed to be administered by anesthesia professionals in medical settings.

As investigators build their case, a central issue is what drugs were in Jackson's system when he died and how those medications were obtained. Jackson's physician, Dr. Conrad Murray, has told investigators he administered propofol and multiple sedatives to Jackson in the hours before he died, the law enforcement official told The Associated Press.

The official spoke on condition of anonymity because the investigation is ongoing.

Los Angeles and Las Vegas police and Drug Enforcement Administration agents served a sealed search warrant Tuesday morning at Applied Pharmacy Services in Las Vegas, which the official said legally sold propofol to Murray. Investigators discovered large amounts of the drug and other medications in Jackson's home after his death. DEA agents were able to track the anesthetic back to the Las Vegas pharmacy.

Through a spokeswoman, Murray's attorney Edward Chernoff said he had not seen the warrant and had no immediate comment.

Murray has talked to detectives but has not spoken publicly since Jackson died. Chernoff has said Murray gave Jackson nothing that "should have" killed him and specifically said the physician did not give Jackson the narcotic painkillers Demerol or OxyContin.

The cause of death for Jackson and details about what was in system will be revealed in the final autopsy report prepared by the Los Angeles County coroner's office. It announced Monday that it has completed its work but won't release findings while the police investigation is ongoing.

Weeks ago authorities served search warrants at Murray's Las Vegas home and his businesses in Las Vegas and Houston, where they seized computer hard drives, medical equipment invoices, phone records and other items. Officials also sought evidence pertaining to the purchase of propofol in those warrants.

Investigators also are looking into Jackson's interactions with at least six other doctors, court documents show.

Michael Flanagan, assistant special agent in charge of the DEA in Las Vegas, said Tuesday's warrant was issued without incident at the single-story business in a strip mall with several other medical services and insurance offices on Flamingo Road, several miles west of the Las Vegas Strip.

The pharmacy staff was cooperative, he said, adding that authorities were searching for any and all paper documents and electronic records. He declined to provide any details.

Pharmacist Jessica Nguyen, who worked at Applied Pharmacy Services for about a month, told the AP that Murray had written prescriptions through the business, though she could not recall specifics. Nguyen now works for a different Las Vegas pharmacy.

A woman who answered the phone at Applied Pharmacy Services after agents left refused to identify herself and declined to comment on behalf of the store and its pharmacist Timothy Lopez.

A telephone voicemail message said Murray's Nevada medical practice, Global Cardiovascular Associates, was closed, effective Tuesday.

Associated Press reporter Oskar Garcia contributed to this report. Watkins reported from Los Angeles.