Heath Ledger Investigation Officially Closed

The U.S. Attorney's Office closed its investigation into Heath Ledger's accidental overdose death and will not enforce a subpoena against Mary-Kate Olsen, a law-enforcement source told PEOPLE.

The probe was closed without any charges being filed.

Olsen, 22, was subpoenaed by a federal grand jury on April 23, but her attorney had been in negotiations with federal authorities since then, the source said.

Olsen had wanted immunity before testifying. Olsen's attorney released a statement saying the actress "had nothing to do" with Ledger's drugs and had already provided "relevant information" to investigators.

The U.S. Attorney's Office and Olsen's rep both declined to comment.

Ledger, 28, was found dead in his Soho apartment on Jan. 22, and the coroner determined the actor died of an accidental overdose of prescription drugs for pain, anxiety and sleep.

I hope Heath's family is relieved. They're one step close to closure now.