Ledger's autopsy results inconclusive

NEW YORK -- A preliminary autopsy on Ledger's body Wednesday was inconclusive.

Ledger was found dead Tuesday by his housekeeper and a massage therapist, police said.

Authorities found six different types of prescription drugs in Ledger's apartment, including pills to treat insomnia and anxiety and an antihistamine, according to two law enforcement officials who spoke on condition of anonymity because the investigation is ongoing. Three of the drugs were prescribed in Europe.

Tests on a rolled-up $20 bill found near the actor's bed detected no drug residue, the NYPD said Wednesday.

Discovery of the bill had raised the prospect that Ledger might have been snorting drugs, but the negative test diminished that possibility.