The doctors who prescribed the medications that led to Heath Ledger’s death are under investigation by federal drug authorities, according to People.com. Ledger, 28, was found dead at his New York apartment on January 22. Autopsy results showed that he died from an accidental mix of prescription drugs. A source told People: “We are investigating doctors in Los Angeles and Texas with regard to Ledger’s prescriptions.” As for whether they believe there were any laws broken, the source said, “We don’t know yet. The agents were there this week, and we are waiting to hear from them.” The investigation is underway to determine whether the drugs were prescribed legally.