Sean Reinert, the pioneering drummer behind several death metal groups, including Cynic and Death, has died. He was 48.

According to officials, Reinert was found unresponsive at his San Bernardino home on Friday, Jan. 24.

No cause of death is known.

Reinert formed Cynic in 1987 with frequent collaborator and guitarist/vocalist Paul Masvidal. They released the cult favorite “Focus” in 1993 before splitting up in 1994. The band reunited in 2006 and released two more albums before Reinert left the group in 2015.

Reinert and Masvidal also worked on Death’s pioneering tech-death metal album “Human” in 1991, which is still considered one of metal’s most influential works. They would later form the group Æon Spoke, which put out two albums.

In 2014, Reinert and Masvidal made national headlines when they publicly came out as gay.

“It’s one thing to make out with your bandmates and just ‘play gay’ because it’s edgy,” Masvidal told the L.A. Times. “It’s another thing to actually live it.” Reinert added: “Gay people are everywhere, doing every job, playing every kind of music and we always have been. It’s taken me years to finally be brave enough to say, ‘If you have a problem with that, then throw out our records. That’s your problem, not mine.'”

Reinert most recently played drums for The Perfect Beings, which released its first record with the drummer in 2018. He also composed music for the 2001 short film, “The Yellow Umbrella.”

On Saturday, Death wrote on its Facebook page: “RIP to an absolute monster and genius on the drums. I’m speechless and have no details.”

News of Reinert’s death was first reported by Blabbermouth.