Theis investigation took place although the doctor is not regarded as a suspect, even though he had been at Jackson's mansion and had made efforts to revive the singer before he died.
DEA spokeswoman Violet Szeleczky was quoted by the AFP news agency as explaining: "What this is, is the Los Angeles police department have an investigation and they came to the Drug Enforcement Agency, and they asked us to help them effect a state search warrant here."
Dr Murray's lawyer, Edward Chernoff, also confirmed that the investigation had taken place at the doctor’s clinic.
