Exhausted after cycling 1, 259 miles in 83 hours as part of an endurance challenge called the Race Across America, he becomes convinced that the motorhome carrying his support team is actually an alien spacecraft, and that his team's pleas for him to come inside and get some rest are merely a cunning pretext to get him to co-operate with a spot of alien probing.

ECONOMIST: A medley of aliens and conspiracy theories

The memo is part of a cache of hundreds of pages of accounts under the heading "Unexplained Phenomenon, " describing claims of UFO sightings, spacecraft debris and alien landings.

CNN: FBI's 'flying saucers' online memo intrigues public