According to the radio report I heard just this morning, it WAS NOT suicide, but Heath Ledger did over-extend himself. Supposedly Heath Ledger was having a hard time playing the Joker because he was working on two projects at once and hardly getting any sleep. Due to the nature of the Joker, acting under sleep deprivation actually helped in playing the role of a psychopathic mass murderer with no empathy. Even after the project was over he had a hard time sleeping and got some prescription sleeping pills and (this is were the news got fuzzy) he either took too many, or took the pills in combination with something else and his heart just failed.