Paul Gray, the bassist with US metal band Slipknot, has been found dead in a hotel in Des Moines, Iowa.
The body of the 38-year-old musician was found by an employee at the hotel in a suburb of the city. Police said foul play was not suspected, but an autopsy will be carried out.
The band, famous for their ghoulish masks, won a Grammy Award in 2006 for the song Before I Forget.
Most of the band members come from the Des Moines area.
The musician had been staying at the TownePlace Suites hotel in the Urbandale area for "a couple of days", Sgt Dave Disney said.
Neil Portnow, president of the Recording Academy, which runs the Grammys, said: "Paul Gray had a passion for music and a flair for the theatrical.
"The band's mix of grinding rap-metal along with their energetic live shows helped establish them as one of the most popular bands in the genre.
"The heavy metal world has lost an immense talent, and Slipknot's loyal following will ensure he and his music are remembered for years to come."
The band's fourth album All Hope Is Gone, released in 2008, gave them their first US number one.
It also topped the charts in Australia, Canada, New Zealand, Austria, Finland, Sweden and Switzerland.
They scored a number one in the UK in 2001 with Iowa, their second album, while All Hope Is Gone reached number two.
They received a total of seven Kerrang! Awards from the UK metal magazine, including best band in the world in 2000 and 2001, and best international band and best live band in 2009.
Jacoby Shaddix, lead singer of metal band Papa Roach, paid tribute, saying: "Paul Gray was an awesome person on and off stage. He will be missed by many including myself.
"His spirit will live on through the killer music he wrote."
The band formed in 1995 in Des Moines and remained based in the city.
Local radio station director Andy Hall, who said he knew Gray for a decade, added: "This is a big blow, not only to the community of Des Moines but fans of metal at large, worldwide.
"It's a devastating loss. Paul was a wonderful human being."
The nine members of Slipknot wore Halloween masks in public and referred to other bandmates by numbers - Gray was number two.
Their extreme stage antics extended to violence against each other and throwing bodily waste, according to Rolling Stone magazine.