DEVOTEES of science fiction have been convinced for decades that an alien spacecraft crashed in the desert of New Mexico - and that the American government covered up the recovery of extraterrestrial bodies.

The so-called Roswell Incident of 1947 spawned conspiracy theories by the score.

Image of a purported "alien" from a documentary on the Roswell incident.

But now, sadly for UFO spotters, a new book offers an entirely man-made and even more bizarre explanation, featuring two of the greatest villains of 20th century history: the Soviet dictator Joseph Stalin and the infamous Nazi ''Angel of Death'' Dr Josef Mengele.

During a powerful storm in July 1947, an object crashed near a rancher's home in Roswell, New Mexico.