FILE - In this July 7, 2006 file photo, Dr. Conrad Murray poses for a photo as he opens the Acres Homes Cardiovascular Center at the Tidwell Professional Building, in Houston. Murray is the target of a manslaughter investigation into the singer's death. A search warrant filed in a Houston court Thursday July 23, 2009 allowed authorities to seek evidence of whether Dr. Conrad Murray committed manslaughter. [Agencies]

LOS ANGELES – Michael Jackson's personal doctor is the target of the manslaughter investigation into the singer's death, according to court documents filed Thursday, the day after agents seized items from the physician's Houston clinic and a rented storage unit.

A search warrant approved by a Houston judge allowed authorities to seek "property or items constituting evidence of the offense of manslaughter that tend to show that Dr. Conrad Murray committed the said criminal offense."

Murray, 51, was with Jackson when he died and has been a central character in the investigation from the outset. The surprise search of his clinic Wednesday indicated authorities were focusing on him, but the warrant language made it clear he's the target.

Los Angeles Police Department spokesman Officer Bruce Borihanh said he could confirm a search warrant was served but had no other comment. LAPD investigators have interviewed Murray twice but haven't labeled him a suspect.

Murray's lawyer, Edward Chernoff, referred queries Thursday to the statement he made a day earlier in which he confirmed a search warrant had been executed and that none of the items seized had previously been requested by authorities.

The documents filed Thursday detailed items taken when federal drug agents and Los Angeles police descended on Murray's clinic. Among them: 27 tablets of the weight loss drug phentermine, a tablet of the muscle relaxant clonazepam, a forensic image of a hard drive, rolodex business cards and e-mails.

The Jackson family has not made any public statements since the search warrant was executed.

Murray, a cardiologist, is licensed to practice in California, Texas and Nevada, and records show he has had no disciplinary actions taken against him.

He was hired as Jackson's personal physician not long before he died. He was in Jackson's rented Los Angeles mansion when the pop star was found unconscious the morning of June 25 and tried unsuccessfully to revive him.

An official determination of what killed Jackson won't be made until at least next week, when the Los Angeles County coroner expects to have a completed toxicology report.

Assistant Chief Coroner Ed Winter said Thursday he had sought information from "seven or eight" doctors and Murray is the only one he has yet to talk to.

Winter said Chernoff had offered to speak with the coroner Friday but without Murray present.

"We don't want to talk to the attorney, we want to talk to" Murray, Winter said.

Chernoff issued a brief statement in response, saying Winter had not made any requests to interview his client.

Jackson had a long history of prescription drug use and unraveling his complicated medical history is a daunting task for investigators, who have said little publicly about what they have found so far.

Propofol, a powerful anesthetic, has emerged as an important part of the investigation. Doses of it were found in Jackson's mansion, according to a person with knowledge of the investigation who is not authorized to speak publicly.

Propofol was not among the items seized under the search warrant, which was approved Monday by Harris County District Court Judge Shawna L. Reagin. The warrant was under seal when it was executed Wednesday; its contents were revealed Thursday when a list of items seized was filed with the court.

A second search warrant, also executed Wednesday, targeted a storage locker Murray rented about five miles from the north Houston clinic. Los Angeles police officers and agents from the Drug Enforcement Administration searched the 10-by-15 foot unit, said Sue Lyon, general manager of West 18th Street Self Storage.

Lyon said she didn't know what was taken, though she did notice authorities gave two itemized sheets of paper to Murray's attorneys who were present.

"It was basically all secretive, and nobody put their nose in nobody's business," Lyon said.

Murray rented the unit April 1, according to Lyon, and while he never visited it personally, others from his clinic did six times — the last time the morning of Jackson's death.