TOPEKA, Kan. (AP) — Authorities in Topeka, Kansas, are investigating circumstances involving a fatally injured man found nude on a street.

Police say 18-year-old Joseph Daniel Irwin of Topeka was found unresponsive, naked and without identification on the street shortly before 8 p.m. Wednesday. He died Friday at a hospital.

Police have not released details about how Irwin may have become injured, only calling the matter “suspicious.” But they have said they are looking for a small, hunter green sport utility vehicle with a roof rack.