The cardiologist who tried to revive Michael Jackson the day he died is being investigated by the Los Angeles Police Department on suspicion of manslaughter, according to two sealed search warrants filed Thursday.

The search warrants confirm that the inquiry into Mr. Jackson’s death last month has become a criminal investigation.

The warrants, filed in Harris County District Court in Texas, were executed by officers with the Los Angeles and Houston police and agents for the Drug Enforcement Administration during the raids Wednesday at an office and a self-storage unit in Houston of the cardiologist, Dr. Conrad Murray.

An inventory of evidence confiscated from the search of the office, at the Armstrong Medical Clinic, includes Rolodex cards, e-mail messages, letters, a phone receipt and two vials of medication — phentermine, an appetite suppressant, and clonazepam, an anti-anxiety drug. Investigators also took a forensic copy of Dr. Murray’s computer.

A list of evidence obtained at a rental storage unit included computer hard drives, compact discs and dozens of documents including a medical suspension notice from a local hospital.

Investigators searched the medical clinic at 10:50 a.m. Wednesday and found receipts for the storage unit, which they raided four hours later.

Charles Lyon, whose wife manages Eighteenth Street Self Storage, said in a telephone interview on Thursday that Dr. Murray rented unit No. 337 on April 1 under the name of Acres Home Heart Vascular Institute.

Mr. Lyon said a Los Angeles police officer and two officers with the Houston Police Department arrived Wednesday afternoon and asked to see the unit.

“Then they went and got a search warrant and I went up there and cut the lock,” he said.

Dr. Murray, who worked in California, Nevada and Texas, is among several doctors police investigators have interviewed in connection with Mr. Jackson’s death. Dr. Murray had been recently hired by Mr. Jackson to attend to him during a planned 50-concert tour.

Ed Winter, the assistant chief coroner for Los Angeles County, said he expected his office to issue a final autopsy report next week.

Coroner officials confiscated several bags of medical supplies and drugs from Mr. Jackson’s Holmby Hills home after his death. The cause of his death has been listed as “deferred” pending a death investigation. A coroner’s official said this week that toxicology test results had been completed, but that the results were being analyzed.

Calls to Dr. Murray’s office and to his lawyer, Ed Chernoff, for interviews were not returned. A statement posted Wednesday on Mr. Chernoff’s Web site confirmed that the authorities were investigating his client on suspicion of manslaughter and that they had taken documents and other evidence from his office.

Dr. Murray was well known in Houston, where he practiced medicine in the predominantly black neighborhood of Acres Home, where his father, Dr. Rawle Andrews, had established himself as one the few black doctors serving the community before desegregation.

“Dr. Murray’s been my doctor five or six years,” said Cuney Williams, who had surgery performed by Dr. Murray. “He saved my life and my husband’s life.”

(Agencies July 24, 2009)