US rock band Train have paid tribute to their founding member Charlie Colin, after his death aged 58, calling him “the sweetest guy”.

His sister confirmed the bass player’s death to the The Associated Press on Wednesday.

The cause of his death is unconfirmed, but his mother reportedly told US website TMZ he died after slipping in the shower, while house-sitting for a friend in Brussels.

The band formed in San Francisco in 1993, and enjoyed one of their biggest hits eight years later, with Drops of Jupiter.