American blues rock star Johnny Winter, known for his slide-guitar solos and raspy vocals, was found dead on Wednesday in a hotel room outside Zurich, Swiss police said. He was 70.
The Texas-born guitarist, vocalist and band leader began performing in his teens, and broke into national fame in 1968, when Rolling Stone magazine dubbed him the hottest musician outside Janis Joplin.
A Swiss prosecutor has ordered an autopsy because the cause of death is unclear.
There was no indication of third-party involvement, and early indications pointed to a medically related incident.
His representative, Carla Parisi, confirmed on Thursday that Winter died in a hotel room in Zurich a day earlier. His death was also reported on his official Twitter account.
A statement said his wife, family and bandmates were all saddened by the loss of one of the world's finest guitarists.
Winter, who was instantly recognisable for his long white hair, had been on an extensive tour this year that brought him to Europe. His last performance was on Saturday at the Lovely Days Festival in Austria.
'Best white blues musician'
In 1969 Johnny played the Newport Jazz Festival, where he performed with B.B. King, one of his musical idols, and at Woodstock.
He also produced albums for his idol, the legendary bluesman Muddy Waters, in the 1970s.
Among Winter's best-known songs was "Still Alive and Well", a blues rock stomper recorded after he resurfaced from heroin addiction in the 1970s. At the height of his career he was considered the best white blues musician.
A new Winter album, on which Eric Clapton and Ben Harper appear as guests, is set to be released on September 2.
A boxed collections of his main tracks since the 1960s was released this year, complete with tributes from other performers who said he'd been a seminal influence on their careers.
Former Guns N' Roses drummer Matt Sorum paid tribute to Winter via Twitter.
In an interview with the New York Times earlier this year, Winter said he enjoyed touring and working with younger musicians.
"I think about legacy a lot," he said. "Hopefully at the end of the day they say I was a good bluesman. That's all I want."