Chris Cornell died via suicide, a medical examiner has confirmed.
Previous reports said the 52-year-old Soundgarden singer was found unresponsive in his hotel bathroom by a friend on Thursday night (NZ time), who had to force open the door.
"At 12am we received a 911 call from the MGM Grand Casino Hotel," Detroit police director of media relations told entertainment magazine Variety.
"It appears as though a family friend was checking up on Cornell at his wife's request. He went to hotel and discovered him unresponsive on the bathroom floor. Police made the location with EMS, and he was pronounced dead at the scene."
Cornell had recently taken the stage at Detroit's Fox Theatre, where the last song he performed with the grunge veterans was Led Zeppelin''s 'In My Time of Dying'.
Led Zeppelin guitarist Jimmy Page took to Twitter to send his condolences, calling Cornell "incredibly talented, incredibly young, incredibly missed".
Cornell battled drug and alcohol addiction earlier in his career, but was reportedly in good spirits at the band's show earlier that night.
He'd tweeted excitedly about Soundgarden's Detroit show just hours before.
"Chris Cornell passed away late Wednesday night in Detroit," a rep for the singer said in a statement.
"His wife Vicky and family were shocked to learn of his sudden and unexpected passing, and they will be working closely with the medical examiner to determine the cause. They would like to thank his fans for their continuous love and loyalty and ask that their privacy be respected at this time."