Manslaughter probe targets Jackson doctor

updated 8:39 p.m. ET July 23, 2009

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.

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."

A receipt for the search warrant detailed items seized when federal drug agents and Los Angeles police descended on Murray's clinic Wednesday. Among them: 27 tablets of the weight loss drug phentermine, a tablet of the muscle relaxant clonazepam, two hard drives, notices from the IRS and a controlled substance registration.

Murray's lawyer, Edward Chernoff, referred queries 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.

Los Angeles Police Department spokesman Officer Bruce Borihanh said he could confirm a search warrant was served but had no other comment.

Murray, a cardiologist, 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.

Video   Hazlett on Jackson investigation July 24: Msnbc.com’s Courtney Hazlett discusses the latest developments in the investigation into Michael Jackson’s death and sorting out the pop star’s estate. Today show

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.

Jackson had a long history of prescription drug use and investigators are speaking with a number of doctors who treated him. Propofol, a powerful anesthetic, has emerged as an important part of the investigation. Doses of it were found in his mansion, according to a person with knowledge of the investigation who is not authorized to speak publicly.

Propofol was not listed on the receipt of items filed in 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 the receipt was filed with the court.

Interactive Michael Jackson’s inner circle The late singer had eight siblings, three children and two ex-wives, plus numerous doctors, advisers, and famous friends. Here's a look at who's who.

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.

Don't miss this on msnbc.com Entertainment In the end, ‘Jon & Kate’ too sad even for fans Tim Burton — the artist — is now on display Can word-of-mouth sell ‘The Road’? Fans either love or really hate ‘New Moon’ Oscar season nears, but where's the buzz? Devoted 'Twihards' get their fix online

MORE FROM MICHAEL JACKSON, 1958-2009

Michael Jackson glove sells for $350,000

Michael Jackson glove sells for $350,000 Warrant: Jackson drugs came from Vegas firm Janet Jackson: Michael in denial over drugs L.A. police want Jackson records sealed Viacom wins rights to Jackson’s ‘This Is It’ Journalists detained after Jackson doctor leaves L.A. pushes to get repaid for Jackson memorial Jackson’s private funeral cost nearly $1 million Judge: Joe Jackson can’t challenge executors FirstPerson: You call ‘This Is It’ ‘raw,’ ‘intimate’   Add Michael Jackson, 1958-2009 headlines to your news reader: