Slipknot bassist Paul Gray was found dead on Monday at a hotel. The circumstances of his death are unclear.

An employee from the TownePlace Suites in Johnston found his body in his hotel room.

CNN has reported that the autopsy showed "No signs of foul play or significant trauma". Gray's cause of death is not yet known and will be determined after toxicology results are returned, which will take four to six weeks.

Slipknot recently held a press conference to pay tribute to Gray.

During the event, the band's remaining members appeared withouth their masks, together with Gray's wife Brenna.

"The only way I can sum up Paul Gray is love," vocalist Corey Taylor said.

Drummer Shawb Crahan said that Gray was the "essence of the band Slipknot" and that he "loved the fans".

"Paul was there from the very very beginning and none of us would be on the path we're on right now in life or have the sorts of lives we have without him," he said.

Crahan added that Gray was "going to be sadly missed and the world is going to be a different place without him."

Slipknot is a nine-piece band famous for the bizarre masks they wear to keep their identities concealed. They were formed back in 1995 in their hometown Des Moines, Iowa.

In 1999, they released their self-titled debut album which sold more than one million copies.

All Hope Is Gone, their 2008 album, went to number 1 in the Australian charts, as well as in the US, Canada, New Zealand, Austria, Finland, Sweden and Switzerland.

Their song Before I Forget won them a Grammy award for best metal performance back in 2004.

Neil Portnow, president and chief executive of The Recording Academy responsible for organising The Grammys, said, "Paul Gray had a passion for music and a flair for the theatrical."

"The heavy metal world has lost an immense talent.

"Slipknot's loyal following will ensure he and his music are remembered for years to come," he added.