FBI investigators want to question Mary-Kate Olsen about Heath Ledger’s death but she won’t talk to the Drug Enforcement Administration (DEA) without granted immunity. The woman who found Ledger’s body contacted her in the first place, before even dialing 911. The police want to know how the actor got to possess and eventually use such powerful painkillers.

Olsen’s lawyers claim that she had already told everything she knew about Heath Ledger’s last days and that she is not a drug consumer. "We have provided the government with relevant information including facts in the chronology of events surrounding Mr. Ledger's death," Michael C. Miller, Olsen’s lawyer said in a statement Monday when he also added " that Ms. Olsen does not know the source of the drugs Mr. Ledger consumed."

DEA investigators suspect the painkillers oxycodone and hydrocodone found in Ledger's system were most likely obtained with phony prescriptions. But some other drugs, like sleeping pills or anti-anxiety medication were legally obtained with medical prescriptions.

Other potential witnesses answered questions about Heath voluntarily, including doctors, Ledger's ex-girlfriend Michelle Williams, and anyone who was in his apartment around the time of his death, the official added. At the moment investigators are in negotiations with Olsen's lawyers.

Heath Ledger’s body was discovered by his masseuse on Jan. 22. Olsen was a close friend of Ledger's. She was in California at the time she received the call but sent her personal security guards to the apartment to help.

Her striving to remain silent may seem a little suspicious, not realizing that her statement could prevent other events like this one to occur in the future.