CHEYENNE, Wyo. (AP) — The family of a University of Wyoming professor missing on a remote Japanese island believes he fell during a hike and didn’t survive, the school said Friday.

Craig Arnold’s family “learned from the private search group it hired that Arnold likely fell from a high and dangerous cliff, and there is virtually no possibility he could have survived the fall,” the university said in a press release Friday.

“We had truly hoped for a different outcome to this story,” UW President Tom Buchanan said. “On behalf of all the faculty and staff at the University of Wyoming, I extend my deepest regrets to Craig’s family and fiancee.”

Phone messages left for Arnold’s sister-in-law were not immediately returned Friday.

Arnold, an assistant professor of English and a published poet, vanished April 26. He was in Japan as part of a creative writing program and was hiking on a volcano on the island of Kuchinoerabu-jima, which is about 30 miles off Japan’s southern Kyushu island.

An American rescue team had no luck on its final day of searching for Arnold, but a Japanese team will continue to search the area identified by the American team, said David Kovar, of the California-based 1st Special Response Group. He said the Americans must leave the island for other commitments.

Kovar said the team tracked Arnold’s trail to the “edge of a very steep drop off, essentially a cliff,” and there was an indication that the professor “did have some sort of accident, slip essentially, at the top of that cliff.”

Kovar said earlier that it would be difficult for Arnold to survive in the area, particularly if he took a fall, but that “people have survived in worse environments.”

A Facebook page set up by Arnold’s fiancee, Rebecca Lindenberg, included a posting Friday that she and his family have concluded he did not survive and that Arnold’s brother Chris will try to find specialists to recover Arnold’s body.

“His trail indicates that after sustaining a leg injury, Craig fell from a very high and very dangerous cliff and there is virtually no possibility that Craig could have survived that fall,” it read.

Arnold, 41, is the author of two award-winning books of poetry. He was in Japan through the U.S.-Japan Friendship Commission’s Creative Artists Exchange Fellowship and was working on a book on volcanoes.