Former Wilco multi-instrumentalist Jay Bennett, 45, died in his sleep in the early hours of May 24. The cause of his death is unknown and an autopsy is being performed, according to published reports.

Bennett released four solo albums and was working on his fifth at the time of his death. His most recent solo project was 2008's "Whatever Happened I Apologize."

His creative partnership with Wilco founder and frontman Jeff Tweedy ended contentiously in 2001, when Bennett was fired from the band over matters of creative direction.

On May 4 of this year, Bennett filed a lawsuit in Chicago's Cook County Circuit Court against Tweedy alleging "breach of contract." He claimed he was owed unpaid royalties for songs released during his seven-year tenure with the band, as well as for appearing in the band's 2002 documentary, "I Am Trying to Break Your Heart.

"We are all deeply saddened by this tragedy," said Tweedy in a statement, who is currently on tour with Wilco. "We will miss Jay as we remember him -- as a truly unique and gifted human being and one who made welcome and significant contributions to the band's songs and evolution. Our thoughts go out to his family and friends in this very difficult time."