DES MOINES, Iowa (AP) — Authorities say rescue crews have been unable to find a man spotted in the Des Moines River.

Des Moines firefighters recovered a boat the man was seen using Monday afternoon. Fire Inspector Brian O’Keefe says the man had pulled the boat from debris upstream from the Scott Street Bridge. He somehow became separated from the boat when he reached the bridge and went over the dam.

O’Keefe says the man may have been living in a homeless camp near the river.