The U.S. Drug Enforcement Administration is investigating where Tyler Skaggs obtained the drugs that were in his system at the time of his July 1 death, according to sources.

An autopsy released Aug. 30 found evidence of fentanyl, oxycodone and ethanol in Skaggs' system when he passed in Southlake, Texas.

A senior DEA official said the agency typically gets involved in fentanyl cases in an effort to track down the source of the drug.

Skaggs was found dead in his hotel room July 1 during a road trip against the Texas Rangers, having choked on his own vomit.