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?

Airs: April 14, 2017 at 9p ET on HLN

'Brokeback Mountain' success helped and hurt Heath Ledger

"Brokeback Mountain" introduced Ledger to girlfriend Michelle Williams, but the movie also brought enormous stress. Watch an excerpt from "How it Really Happened" Fridays on HLN.

Why was Mary-Kate Olsen called the night Heath Ledger died?

A masseuse, sleeping pills and Mary-Kate Olsen all came up in the investigation into the night that Heath Ledger died.

Season 1: Episodes