Last week authorities raided Murray's medical offices in Houston, using a search warrant that authorised them to collect evidence of manslaughter.

The results of two autopsies have not yet been released pending toxicology reports, but investigators reportedly believe that Jackson used propofol administered intravenously as a daily sleep aid. Murray was the doctor hired to be at Jackson's side through his 50 concert comeback engagement in London and was with Jackson when he died June 25.

Murray's lawyer has previously denied that he gave Jackson any drugs that could have led to his death.