Mary-Kate Olsen is looking for immunity from prosecution in the Heath Ledger overdose death case. Mary-Kate’s cooperation in the federal investigation is contingent upon immunity.

Mary-Kate Olsen could be subpoenaed by investigators – questioning the actress about her role in 28-year-old Ledger’s death on January 22. As you may recall, he was discovered by his masseuse, who then called Mary-Kate Olsen before calling 911.