"We are in a state of unfathomable sadness and grief," Hinds' former bandmates wrote in an emotional tribute to the late heavy metal rocker.

Brent Hinds, the former singer-guitarist for the Grammy-winning heavy metal band Mastodon, has died in a motorcycle accident in Atlanta, the band and authorities said. He was 51.

Mr. Hinds, 51, was found unresponsive late Wednesday after an S.U.V. appeared to slam into the motorcycle he was riding near downtown Atlanta, the authorities said.