Two doctors who prescribed pills to Heath Ledger are now being probed by federal drug investigators. One doctor in California and another in Texas are said to have prescribed the painkillers OxyContin and Vicodin to the Brokeback Mountain star, who died on January 22 of an accidental overdose of six prescription drugs, which included sleeping pills and anti-anxiety medicine. What is under investigation is whether or not the drugs were prescribed illegally, reports the New York Daily News. "It's an ongoing investigation," a law enforcement insider told the newspaper. "It's not clear if there was any wrongdoing." In the meantime, the medical examiner's findings in Heath's death have been subpoenaed by the federal Drug Enforcement Administration, as the agency probes the two doctors. Whether this will help bring closure to Heath's family and friends is doubtful.