Avenged Sevenfold drummer Jimmy "The Rev" Sullivan died of an accidental drug overdose, according to a coroner's report from the Orange County Sheriff's Department.

Sullivan was found dead at his home Dec. 28, and the cause was initially unclear. The coroner's report, which officially signed June 1, declares that Sullivan died from the combined effects of four drugs: oxycodone, oxymorphone, diazepam/nordiazepam and ethanol.

The report also states that Sullivan's heart and liver were enlarged during the Dec. 29 autopsy.

Sullivan, who also wrote and sang for Avenged Sevenfold, grew up in Huntington Beach.