US Federal investigators raided a Las Vegas pharmacy searching for documents relating to Dr Murray, as they probe Michael’s death.
Agents from the Drug Enforcement Administration (DEA) arrived at Applied Pharmacy Services in Las Vegas searching for evidence relating to prescriptions written by Dr Murray.
It followed similar raids at Dr Murray’s house and offices last month.
Police are reportedly working on the theory that the doctor administered the powerful sedative Propofol shortly before Michael’s heart stopped.
Dr Murray, Michael’s personal physician, was with him at the time of death and it has been suggested the medic administered a powerful drug to help Michael sleep in the hours leading up to his death.
It is understood that during Tuesday’s raid DEA agents were looking for prescriptions written by Dr Murray for Michael or under any aliases.
It is the latest in a number of warrants placed on premises connected to Dr Murray. His home and office in Las Vegas was raided last month, as was a site in Houston, Texas, connected to the doctor and Dr Murray has been quizzed twice by police as part of their probe and a third interview is planned.
He has not been named as a suspect, but court records have identified the 51 year old physician as the suspect of a manslaughter investigation.