Three Drug Enforcement Administration employees were among the 14 Americans killed Monday when three helicopters crashed in Afghanistan. They were the first DEA personnel to lose their lives in the country. Enemy fire was ruled out as causing the crash in the southern region that killed four Americans, according to NATO’s International Security Assistance Force. Enemy action was also not suspected in a separate incident when a helicopter returning from a raid on a compound went down in the western region, killing seven American troops and three American civilians working for the government. The tally marked the largest number of American citizens killed in Afghanistan in more than four years, according to CNN. ISAF is currently investigating both incidents, and the names and service branches of the deceased troops have not yet been released.