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TV Guide is reporting that the DEA is launching an investigation into how Heath obtained the lethal combination of prescription drugs that ultimately let to his death.

Apparently, the DEA has already requested a copy of the autopsy (which found traces of oxycodone, hydrocodone, diazepam, temazepam, alprazolam, and doxylamine) and the original police report.

It was previously reported that Heath held prescriptions for at least three of those medications: diazepam (aka Valium), temazepam (aka Restoril), and alprazolam (aka Xanex).