The Mainliner Explosion A few minutes past 7 p.m, the evening of Nov 1, 1955, a United Airlines DC-6B Mainliner plane exploded 11 minutes into it 1,075-mile final stretch of its daily route from New York to Portland, via Chicago and Denver, ending 44 lives. Four veteran CAB investigators, representatives of the Douglas Company- the plane's manufacturer, and over 60 of United's top technical men, were rushed to the crash scene, a gently rolling area of ranch and farmlands northwest of Denver, dotted by cattle corrals, haystacks, and irrigation ditches. Among the first on the scene were a group of U.S. Postal Inspectors. To the Postal Inspection men, trained in the techniques of revenge-seekers, the cause of the crash was no mystery. Scorched and shredded envelopes known to have been carried in the luggage compartment immediately told the Postal inspectors that Flight 629 had been blasted by a dynamite bomb put aboard in Denver. Anatomy of A Trial: Based on hundreds of pages of FBI documents and court transcripts, The Mainliner Explosion is the only in-depth account of the crash which marked a turning point in airline history - the first bombing of a commercial aircraft in U.S. history - and the bomber's murder trial - a trial which posed many challenges to justice.