What Killed Heath Ledger

To many, Heath Ledger had it all --baby and burgeoning career, but this episode reveals things are not as they seem. Ledger finished filming his Oscar-worthy performance of his gritty portrayal of the Joker in the "The Dark Knight." Ledger's body was found in his apartment and investigators were led to discover bizarre drawings and puzzling clues, including a diary Ledger created detailing his immersion of the Joker persona. Did this dark role impact his real life and what was his connection to Mary-Kate Olsen?