E! News reported Steuer's death, but said the cause of it has not been made public.
"It is with heavy hearts and saddened minds that we announce the passing of our dear friend and singer Jonny Jewels, AKA Jon Paul Steuer," his band's Facebook page read this week.
"The addition of Jonny to our dysfunctional band family was one of the best choices that we have ever made, and he brought a much needed sense of fun and lightheartedness to everything we did," the message continued.
"He was only with us for a little more than a year, but we managed to cram a lifetime of great experiences into his tenure as our singer: dozens shows at home in Portland and across several states, an amazing European tour, and our best full-length release yet."
"We've lost our singer, but far, far more than that we've lost a friend. Rest in peace, Jonny...we love you. Jon Paul Steuer March 27, 1984 - January 1, 2018."
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