Honolulu police were investigating the discovery of 19-year-old man with suspicious injuries found Sunday morning on the side of Kalanianaole Highway in Waimanalo.

They say officers responding to a report of an unconscious male on the side of the road found the man just after midnight about four-tenths of a mile south of Bell Street. An ambulance transported the man in serious condition to an area hospital where his condition was downgraded to critical.

A bystander reported hearing a loud thud about 11:30 p.m. Saturday and saw a red pickup truck, possibly a Ford F-150 or F-250, leaving the area.