The Australian-born actor was found dead Tuesday by his housekeeper and a massage therapist - lying naked and face-down on the floor at the foot of his bed, police said. Prescription sleeping pills and anti-anxiety pills were found in bottles in Ledger's bedroom and bathroom, and police said the death was caused by a possible drug overdose and appeared to be accidental.
Ellen Borakove, a spokeswoman for the medical examiner's office, said the autopsy on the 28-year-old actor was inconclusive and that more would be known after more thorough tests can be completed. That process was expected to take about 10 days.
Fans remembered left flowers and candles outside his Manhattan apartment on Wednesday. News of the death stunned family, fans and colleagues.
"Working with Heath was one of the purest joys of my life," said Ang Lee, who directed Ledger in "Brokeback Mountain."
"He brought to the role of Ennis more than any of us could have imagined - a thirst for life, for love and for truth, and a vulnerability that made everyone who knew him love him. His death is heartbreaking."
Speaking in Australia, Ledger's father called the death "tragic, untimely and accidental."
Kim Ledger called his son "down-to-earth, generous, kind-hearted, life-loving, unselfish" and "extremely inspirational to many."
"Heath has touched so many people on so many different levels during his short life," he said. "Please now respect our family's need to grieve and come to terms with our loss privately."
Khaled Ali, 41, a stage manager for a Broadway show, dropped off a candle outside Ledger's building on his way to work Wednesday morning. He said he and his fellow cast members were devastated.
"I felt a connection with him as an actor, as a fellow in the theater community," he said. "With `Brokeback Mountain' he touched me personally in telling the story of my community. It was very touching."
Ledger was known for grueling, intense roles that became his trademark after he got his start in teen movies like "10 Things I Hate About You." Thereafter, he avoided the easy path in favor of roles that forced him to bury his Australian accent and downplay his leading-man looks: the tormented gay cowboy Ennis Del Mar in "Brokeback Mountain"; a drug addict in "Candy"; an incarnation of Bob Dylan in "I'm Not There."
Playing the Joker, in the upcoming Batman movie "The Dark Knight," may be his final finished performance.
Ledger split last year with Michelle Williams, who played his wife in "Brokeback." The two had a daughter, the now 2-year-old Matilda, and had lived together in Brooklyn's Boerum Hill neighborhood.
Early Wednesday, Williams and Matilda left Trollhattan, Sweden, where the 27-year-old actress had been shooting scenes for the upcoming film "Mammoth," said Martin Stromberg, a spokesman for film production company Memfis Film.
"She received the news at her hotel late last night," Stromberg said, adding he had not spoken to the actress after she learned of Ledger's death.
The actor's personal strife was accompanied by professional anxiety. He said in a November interview that "Dark Knight" and "I'm Not There" took a toll.
"Last week I probably slept an average of two hours a night," Ledger told The New York Times. "I couldn't stop thinking. My body was exhausted, and my mind was still going." He said he took two Ambien pills, which only worked for an hour.
News of Ledger's death spread quickly, from the crowd of 300 people that gathered Tuesday outside his Manhattan apartment to the Sundance Film Festival in Utah, where those with close ties to the actor included Naomi Watts. A publicist for Watts said the actress, who had a previous relationship with Ledger, had left the festival on Tuesday night.