Federal agents have launched an investigation into claims that high-powered explosives have gone missing from a Marine Corps training installation in California. About 10 pounds of composition C-4 plastic explosives disappeared from Marine Corps Air Ground Combat Center Twentynine Palms during a January exercise, ABC10 News in San Diego reported. The Naval Criminal Investigative Service is investigating the matter, said Jeff Houston, a spokesman for the agency. Marine Corps officials referred questions -- including when the explosives are believed to have gone missing, how they're typically safeguarded, what units were involved in the recent exercise, and whether any suspects have...