A bomb was set off in Blacksburg, Va., early Wednesday, badly damaging a sport utility vehicle, police said. Officers responded to a report of either a gunshot or an explosion about 2:50 a.m., WSLS-TV, Roanoke, reported. An initial investigation determined an improvised explosive device was set off near several parked vehicles, causing substantial damage to one of them. No one was hurt in the blast. A red Chevrolet Blazer was the suspected target of the blast and was towed away from the scene with a tarp covering it. Virginia State Police, the FBI and Bureau of Alcohol, Tobacco, Firearms and Explosives agents were assisting Blacksburg police with the investigation.