Tyler Skaggs' death in a Southlake hotel on July 1 is being investigated by the U.S. Drug Enforcement Administration, ESPN's Outside the Lines reports.
The DEA wants to determine where Skaggs obtained the drugs that were found in his system.
Autopsy results found evidence of fentanyl, oxycodone and ethanol in Skaggs' body. The fentanyl drew the attention of federal investigators, the source told ESPN's T.J. Quinn.
The synthetic opioid was also found in the autopsy reports after the deaths of rock stars Tom Petty and Prince.
"We continue to cooperate with law enforcement on this important matter," Angels team spokesperson Marie Garvey told ESPN.
Skaggs, 27, was staying in the Angels' team hotel in Southlake during a roadtrip to play the Texas Rangers in Arlington.
Skaggs' family vowed to "not rest until we learn the truth about how Tyler came into possession of these narcotics, including who supplied them," when the autopsy was released on Aug. 30.
ESPN reports that no Angels' player has been publicly named as being connected to his death, or as a target in the investigation.
