VISTA, Calif. -- San Diego County prosecutors said Thursday they will not charge a 92-year-old man who drove off after hitting and killing a teenager in Vista.

Deputy District Attorney Jodi Breton said there is not enough evidence to show that the driver knew he'd hit a person.

The man struck 15-year-old Lucas Giaconelli the evening of Jan. 29 as the teen was skateboarding on a road with friends. Investigators determined that the teen was wearing black and was in an unlighted area when he veered into the car's path, according to authorities.

The car did not stop but an elderly man who lives near the crash site approached a sheriff's deputy during a memorial for the boy the next night.

The man told authorities that he had hit something but thought it was an object or an owl and kept on going.