Avenged Sevenfold Drummer James 'The Rev' Sullivan Autopsy 'Inconclusive'

Authorities have ordered additional tests, which are expected to take several weeks.

Authorities have ordered additional tests after an initial autopsy on Avenged Sevenfold drummer James "The Rev" Sullivan was inconclusive. According to The Associated Press, the autopsy seeking a cause of death for the 28-year-old rock drummer, who was found unresponsive in his Huntington Beach, California, home Monday, did not turn up definitive evidence of what caused his sudden demise.

Orange County sheriff's spokesman Jim Amormino told the AP on Tuesday that the county coroner's office has ordered toxicology, microscopic and laboratory tests to help determine what caused Sullivan's death. The tests are expected to take several weeks.

Police said Monday that Sullivan appeared to have died of natural causes.

"It is with great sadness and heavy hearts that we tell you of the passing today of Jimmy 'The Rev' Sullivan," the band announced on its Web site. "Jimmy was not only one of the world's best drummers, but more importantly he was our best friend and brother. Our thoughts and prayers go out to Jimmy's family and we hope that you will respect their privacy during this difficult time. Jimmy you are forever in our hearts. We love you."

Sullivan was one of the co-founders of the group, which came together in Huntington Beach, California, in 1999 and won the Best New Artist award at MTV's VMAs in 2006, thanks to their hard-driving metal sound, which mixes in elements of emo and punk.

Sullivan, known for his propulsive drumming, backing vocals and creative songwriting, was honored by a number of his metal kin, who praised his abilities and nature.