Heath Ledger's autopsy likely to be released today

It's a "big possibility" that Heath Ledger's autopsy results will be released as early as Tuesday, a spokeswoman for the New York City Medical Examiner's office has said.

According to US reports, the new findings will supplement those of the initial autopsy - results of which proved inconclusive.

The initial autopsy results were released on Jan. 23, a day after the 28-year-old actor was found dead.

"The autopsy was inconclusive," Medical Examiner spokeswoman Ellen Borakove told American magazine People on Jan. 23. "We have to do further testing including toxicology and tissue testing. Neither cause of death or manner of death has been concluded."

Michael Baden, a forensic expert (not involved with the investigation) said the initial inconclusive finding "rules out the natural causes, such as a brain hemorrhage, pneumonia or a cardiac abnormality."

"That leaves drug overdose as the most likely cause of death," Baden said.

Ledger - whose most notable role was as a gay cowboy struggling with his sexuality in the cult hit 'Brokback Mountain' - was found dead in his downtown Manhattan apartment on Jan 22. He was 28. He had a daughter, Matilda, 2, with ex-fiance Michelle Williams - who has been left "heartbroken" over the actor's untimely death.