DEA Subpoenas Heath Ledger's Death Records
02/08/2008 AT 02:30 PM EST
The subpoena, served on the New York City Medical Examiner's Office, is standard DEA procedure when someone dies from an accidental overdose, the source says.
"Usually with an accidental overdose we try to identify if any medication was overly disbursed," the source said.
Ledger, 28, died of an accidental mixture of prescription drugs, including Oxycodone, Hydrocodone, Diazepam, Temazepam, Alprazolam, and Doxylamin, the Medical Examiner determined.
DEA investigators will interview the physicians who prescribed Ledger the drugs to "make sure there was a medical condition attached to the medication," the source said.
The investigation could take anywhere from five days to two weeks, the source said.