The football player had apparently been involved in an argument with his fiancée at a home when she drove away in a pickup truck. Henry jumped onto the bed of the truck, but fell out of the vehicle about a half-mile away.
A police spokesperson said homicide detectives were assigned to the case, but that no charges have been filed.
A seemingly perpetually troubled player, the hot-tempered Henry was arrested at various times for marijuana possession, gun possession and assault, earning him the epithet of "one-man crime wave" from a judge – and his ouster from the Cincinnati Bengals in 2008.
But after the Bengals' owner gave Henry a second chance, the athlete seemed to have straightened out, staying out of trouble and focusing his off time on his fiancée and the three children they were raising.