The Okaloosa County Sheriff's Office and Hurlburt Office of Special Investigation discovered an explosive device in the back of a truck that had base access after receiving an anonymous tip Tuesday morning. At about 6 a.m., deputies received an untraceable call and alerted Hurlburt Security personnel of the potential danger. The male voice had warned that a man working at Hurlburt Field had explosives on his truck. Hurlburt Field security levels were raised at 10 a.m. when morning searches for the truck came up empty. The caller's partial description eventually led investigators to a man with access to the base...