Heath Ledger's initial autopsy 'inconclusive'

An initial autopsy into the death of Hollywood actor Heath Ledger was 'inconclusive', according to U.S reports.

The New York City Medical Examiner carried out the autopsy on Ledger at its Manhattan base to try and determine what killed him.

Police officers say that they discovered a string of prescription and non-prescription sleeping medication in the apartment where the 'Brokeback Mountain' star was found dead on Tuesday.

Police insiders say they believe that Ledger's death was most probably an accidental one and not suicide.

Now the Medical Examiner's office will carry out additional tests, which could take up to ten days to complete, TV station 'NBC 4' is reporting.