Heath LedgerHeath Ledger (Photo: Bryan Bedder/Getty Images)

Updated, 5:28 p.m. | The actor Heath Ledger was found dead this afternoon in an apartment in Manhattan inhabited by the actress Mary-Kate Olsen, according to the New York City police. Signs pointed to a suicide, police sources said. Mr. Ledger was 28.

At 3:31 p.m., a masseuse arrived at Apartment 5A in the building, at 421 Broome Street in SoHo, for an appointment with Mr. Ledger, the police said. The masseuse was let in to the home by a housekeeper, who then knocked on the door of the bedroom Mr. Ledger was in. When no one answered, the housekeeper and the masseuse opened the bedroom and found Mr. Ledger naked and unconscious on a bed, with pills scattered around his body. They shook him, but he did not respond. They immediately called the authorities.

The police said they did not suspect foul play. The police said they believed Ms. Olsen, 21, was in California and said it was not clear why Mr. Ledger was in her apartment.

Mr. Ledger, a native of Perth, Australia, won acclaim for his role as a co-star in “Brokeback Mountain” (2005). The film, based on a short story by Annie Proulx about two cowboys who fall in love, won critical acclaim. Reviewing the film in The New York Times, the critic Stephen Holden wrote, “Mr. Ledger magically and mysteriously disappears beneath the skin of his lean, sinewy character. It is a great screen performance, as good as the best of Marlon Brando and Sean Penn.”

Mr. Ledger met the actress Michelle Williams while filming ‘’Brokeback Mountain.” The two actors fell into a romance and moved to Boerum Hill, Brooklyn, where their comings and goings were widely noted by paparazzi. They had a daughter, Matilda Rose, who was born on Oct. 28, 2005. The couple separated last year.

In an interview in London for an article published in November, Mr. Ledger told The New York Times, ‘’I feel like I’m wasting time if I repeat myself.” He said in the interview that he was not proud of his latest role, in Todd Haynes’s “I’m Not There,” in which Mr. Ledger was one of a half-dozen actors depicting the musician Bob Dylan. ‘’I feel the same way about everything I do. The day I say, ‘It’s good’ is the day I should start doing something else,” said in the interview.

Calls by The Times to Mara Buxbaum, a publicist for Mr. Ledger, and Steve Alexander, the actor’s agent, were not immediately returned this afternoon.

Thomas J. Lueck contributed reporting.