TAMPA, Fla. (AP) — Paul O’Neill, the founder of the progressive metal band Trans-Siberian Orchestra, died of an accidental drug overdose, a Florida medical examiner said in a report released Tuesday.

The Hillsborough County Medical Examiner in Tampa wrote in an autopsy report dated May 25 that O’Neill had methadone, codeine, diazepam and an antihistamine in his system when he died April 5 in Tampa. The county released the report on Tuesday.

The cause of death for the 61-year-old was intoxication and the manner of death was drug abuse. He was found dead in a hotel room.

O’Neill was a rock producer and manager who founded Trans-Siberian Orchestra in 1996, blending heavy metal with classical music and creating a unique brand of rock theater. He tapped three members of the Tarpon Springs, Florida, band Savatage to be part of TSO and intended for it to be a “supergroup,” similar to popular bands like ELO, Pink Floyd and Yes.

The band is best known for its takes on Christmas staples like Carol of the Bells, but also more experimental, arena-rock songs such as Christmas Eve (Sarajevo 12/24), which described a lone cello player playing a forgotten holiday song in war-torn Sarajevo. That song was on the band’s 1996 album, Christmas Eve and Other Stories, which went triple platinum.

Fans especially loved the band’s Christmas tours, which were heavy on guitar solos and heavier on special effects — similar to a Broadway Christmas pageant with a heavy metal soundtrack. One magazine once wrote that “TSO has enough pyro to BBQ an entire…