"The autopsy was inconclusive," New York City Medical Examiner spokeswoman Ellen Borakove tells PEOPLE. "We have to do further testing including toxicology and tissue testing. Neither cause of death or manner of death has been concluded. We expect additional results in 10 days to two weeks."
The 28-year-old star's body was found in the bedroom of his downtown New York City apartment, with prescription sleeping medication nearby.
Another medical-examiner's office spokeswoman, Grace Brugess, also told PEOPLE on Wednesday that Ledger's body is ready to be claimed by the family, which, she said, is still working on funeral arrangements.
Ledger had pneumonia at the time of his death, PEOPLE has confirmed.
Pneumonia Ruled OutYet Michael Baden, a prominent forensic pathologist not involved with the investigation, tells PEOPLE that if the pneumonia had been the cause of the actor's death, that would have been evident in Wednesday's initial results, given that it is "readily identifiable at the time of autopsy, because the lungs, instead of being filled with air, are filled with fluid, and we die from pneumonia because we can't breathe."
He notes: "I would assume under the circumstances that if he'd die of pneumonia that would be clearly stated, because of concerns from the family."
As for the meaning of "inconclusive," Baden said, "My interpretation means they didn't find a proper cause of death. That kind of rules out the natural causes, such as a brain hemorrhage, pneumonia or a cardiac abnormality that is common in that age group. That leaves drug overdose as the most likely cause of death."
He adds, "That still needs an interpretation as to intentional or unintentional, but that's done by gathering information about his mental health and his recreational activities by interviewing physicians, neighbors, friends and family."
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