After their tiny plane crashed deep in the jungles of southern Colombia, three American civilians on a mission to search for cocaine labs, drug planes and, occasionally, guerrilla units were taken hostage by Marxist rebels. A year later, the men's families say the captives have been all but forgotten. Some say that is the way American officials and the men's employers want it to be. The three Americans โ Marc Gonsalves, Keith Stansell and Thomas Howes โ worked cloaked in secrecy for two subsidiaries of Northrop Grumman, the huge military contractor, in an arrangement used increasingly by the United States...