(FROM AP) ? After an autopsy on Heath Ledger came back inconclusive on Wednesday, a medical examiner’s office spokesperson said it will be about 10 days before authorities know more about what killed the 28-year-old actor. Ledger’s body was found lying face down in his apartment on Tuesday afternoon. The AP reports that there were several different kinds of prescription pills found at the scene, including pills to treat insomnia and anxiety, and an antihistamine, according to two law enforcement officials. Police said no illegal drugs were found. Ledger will appear in the next Batman movie The Dark Knight and was working on Terry Gilliam’s The Imaginarium of Dr Parnassus, which also features Christopher Plummer. (AP via Yahoo!)