Jeff Austin, a revered bluegrass musician and one of the co-founders of the Yonder Mountain String Band, has died. He was 45 years old.

Austin died on Monday (June 24), in Seattle, Wash., according to a statement on his Facebook page, but the cause of his death has not been specified. A rumor that the singer and mandolin player had died began circulating over the weekend; it proved to be false, although Austin did post on Saturday (June 22) that he would be canceling some upcoming performances due to an unspecified medical emergency.

A Chicago-area native, Austin moved to Nederland, Colo., after college (University of Cincinnati), with friend and then-bandmate David Johnston. Together with Ben Kaufman and Adam Aijala, they founded the Yonder Mountain String Band in 1998. He left the group in 2014.

"We are saddened to report that we have lost our brother Jeff Austin," YMSB write on Facebook. "Remembering the incredible times and magical moments puts us at a profound loss for words. While we honor his memory, we will continue to pray for his family and for the journey they now face without him. "

While with Yonder Mountain String Band, Austin participated in a few side projects, including a live album of bluegrass-leaning Grateful Dead covers -- under the name Grateful Grass -- and 2004's Songs From the Tin Shed, a record of cowboy songs. He founded the Jeff Austin Band after leaving YMSB.

Austin leaves behind his wife Devlyn and three children: 12-year-old Lily Rose, 5-year-old Penelope and 2-year-old Jude Patrick. A fund has been set up to help them.

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