A kayaker from Denver was found dead in Yellowstone National Park earlier this week.

According to a release from the National Parks Service, boaters on Yellowstone Lake on Monday found the body of Brandon Rhea, 41, of Denver. He was found floating in the water on the northwest shore of the lake.

Park rangers responded to the scene and recovered Rhea’s body, and also found a capsized kayak and personal belongings.

Authorities are investigating the incident. They did not say how Rhea is believed to have died.