NEW YORK (AP) -- The medical examiner's office says an autopsy on actor Heath Ledger was inconclusive, and more tests are needed.
A spokeswoman for the office, Ellen Borakove, said Wednesday that it will take about 10 days to complete the investigation.
Meanwhile, Ledger's family says his death was an accident.
His father Kim read a statement to reporters in Australia, describing his son as a "down to earth, generous, kind-hearted, life-loving unselfish individual" who was "extremely inspirational to many."
The 28-year-old was found dead Tuesday afternoon in his New York apartment. There were sleeping pills nearby but police say there's no obvious sign that he took his own life.
The actor, who was nominated for an Oscar for his role in "Brokeback Mountain," told The New York Times in a November interview that he had "stressed out a little too much" and had trouble sleeping while making his latest movies.
He had recently finished filming his role as the Joker in "The Dark Knight," a sequel to 2005's "Batman Begins."
Mel Gibson, who played Ledger's vengeful father in "The Patriot," said in a statement that Ledger "was just taking off, and to lose his life at such a young age is a tragic loss."
NYPD spokesman Paul Browne told The Associated Press that Ledger had an appointment for a massage at his Manhattan apartment. The housekeeper went to let Ledger know the masseuse was there and found him dead at 3:26 p.m.
The Australian-born actor was nominated for an Oscar for "Brokeback Mountain," where he met his wife, actress Michelle Williams, in 2005. Ledger and Williams had lived in Brooklyn and had a daughter, Matilda, until they split up last year.
Ledger's roles include the suicidal son of Billy Bob Thornton in "Monster's Ball" and had starring roles in "A Knight's Tale" and "The Patriot."
Ledger was born in 1979, grew up in Perth and began doing amateur theater at age 10. At 16, he moved to Sydney to pursue an acting career, quickly landing TV movie roles and guest spots on Australian television.
After several independent films, Ledger moved to Los Angeles and co-starred in "10 Things I Hate About You," a teen comedy reworking of "The Taming of the Shrew."
WLTX.com will have more information as it becomes available.