Heath Ledger's Autopsy Result's Subpoenaed

U.S federal officials have subpoenaed Heath Ledger’s autopsy results as part of their investigation into the actor's accidental overdose.

The Drug Enforcement Agency (DEA) have issued the New York Medical Examiner's Office with the legal paperwork as part of their standard procedure when a person, such as Ledger, dies from an accidental overdose on perscription medicine.

A New York City Medical Examiner on Wednesday ruled that the Brokeback Mountain star died from an accidental overdose of six prescription medications, including painkillers, sleeping pills, anti-anxiety pills and antihistamines.

DEA spokesman Erin Mulvey said on Thursday:  "We are working with the New York Police Department to identify any illegally prescribed drugs that may have been prescribed to Ledger."

Ledger was buried at his family's plot in Karrakatta Cemetery in his native Perth, Australia on Saturday.