NEW YORK (Reuters) - Federal prosecutors in New York have closed an investigation into the fatal prescription drug overdose of actor Heath Ledger without bringing charges, People magazine reported on its Web site on Wednesday.
The report, citing an unidentified law enforcement source, also said the U.S. Attorney's Office will not enforce a subpoena issued in the case by a federal grand jury against actress Mary-Kate Olsen.
Federal authorities involved in the case could not immediately be reached for comment. Olsen's lawyer, Michael Miller, declined to comment.
Olsen, 22, was a friend of the 28-year-old Australian actor and the first person called by his masseuse when he was found dead in his New York apartment in January. She summoned private security guards who arrived at the scene about the same time as emergency medical personnel.
The cause of Ledger's death was later ruled an accidental overdose of prescription medications, including the painkillers oxycodone and hydrocodone.
A law enforcement source told Reuters on Monday the U.S. Drug Enforcement Administration was conducting an inquiry into the source of those medications and that Olsen had declined to speak with investigators unless granted immunity from prosecution.
Ledger was nominated for an Oscar for his role as a gay cowboy in 2005's "Brokeback Mountain." His final role as the villainous Joker in the Batman sequel "The Dark Knight," released last month, is being critically hailed with Internet buzz touting him as an Oscar candidate in 2009.
Ledger has a 2-year-old daughter, Matilda, by his "Brokeback Mountain" co-star, Michelle Williams.