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Federal drug authorities are investigating doctors in Texas and in California in connection with Heath Ledger's death last month, according to the NY Daily News.

Autopsy results reported an accidental mixture of prescription drugs and now docs in two states are being investigated for possibly having supplied Ledger with Oxycontin and Vidodin. Authorities want to know if the drugs were prescribed illegally, according to the News. A law enforcement source told the paper, "It's not clear if there was any wrongdoing."

Ledger died on January 22; he was found in his SoHo apartment by his housekeeper and a masseuse. Ledger is survived by his daughter Matilda and her mother, Michelle Williams.