RIVERTON, Wyo. (AP) — A 31-year-old Utah man has died in a bear attack in the Bridger-Teton National Forest in central Wyoming.

Officials aren't certain yet what type of bear killed Adam Thomas Stewart of Virgin, Utah.

Fremont County Undersheriff Ryan Lee says Stewart was in a remote area checking on a research plot during earlier this month.

He failed to return, prompting a search that began on Sept. 8. His body was found last Friday between his campsite and the research plot.

Lee declined to release details as to why authorities believe it was a bear attack.