Drugs agents probing Michael Jackson's death have raided the Houston clinic of his 'live-in' doctor for evidence of manslaughter.

A team of 20 officers from the Drugs Enforcement Agency and two robbery-homicide detectives from the Los Angeles Police took part in the sweep at the Armstrong Medical Clinic this morning.

The medical facility is the Houston base of Dr Conrad Murray, who was with Jackson in Los Angeles when he suffered a cardiac arrest on June 25.

Dr Murray’s lawyer Ed Chernoff said a search warrant authorised detectives to “seize items, including documents, they believed constituted evidence of the offence of manslaughter”.

Dr Murray's Houston clinic during Wednesday's raid (Splash News)

The agents left with a "forensic image" of a computer hard drive and 21 documents, Mr Chernoff said.

He added: "None of the documents taken had previously been requested by law enforcement or the LA Coroner's office."

Dr Murray’s spokeswoman had earlier told the BBC the raid "was a surprise to us and it was a surprise to the attorneys".

Meanwhile, it has been confirmed that police have requested a third interview with Dr Murray, who is not considered a suspect in Jackson's death.

The police investigation has come to focus on the singer’s alleged addiction to prescription medication.

Dr Murray’s lawyer has already denied US media reports that claimed his client had injected the star with a drug similar to morphine in the hours before his death.

Dr Murray poses at his Los Angeles clinic before Jackson's death (Splash News)

The Los Angeles Coroner's office has deferred Jackson's cause of death pending the results of toxicology tests.

Authorities search the Houston office of Dr. Conrad Murray, Michael Jackson's personal physician, for the powerful anesthetic Propofol.

The LAPD, which has been in charge of the investigation, served a warrant to Murray's office at Houston's Armstrong Medical Clinic. Murray was reportedly present on June 25 at the time of Jackson's death.

Community activist, Quanell X, arrived on behalf of Dr. Davill Armstrong, the clinic's namesake, who was assured by DEA agents he is not a target of the investigation and his name was not on the search warrant.