Two American doctors are under investigation in connection with the accidental death of Heath Ledger. The doctors, one from California and the other from Texas, are being looked at by federal drug authorities, according to reports. Ledger's body was found in his Manhattan apartment in January, and an autopsy blamed the fatal mixture of prescription drugs. The doctors being probed are believed to have supplied Ledger, 28, with the drugs Oxycontin and Vicodin, People.com reports. An insider told People,

"We are investigating doctors in Los Angeles and Texas with regard to Ledger's prescriptions. It is unclear yet whether there was any wrongdoing by whether doctor. We don't know yet. The agents were there this week, and we are waiting to hear from them."

The Drug Enforcement Administration has already subpoenaed the results of an autopsy carried out on Ledger in New York. The autopsy concluded that the drugs Valium, Temazepam, Alpazolam and Doxylamine were also present in the actor's body.