Austrian Rocket pioneer Hermann Oberth gave some credence to the story later that year, referring to a pilot killed on a suborbital flight but didn't add any substantial information. Nevertheless, the seed of a secret Soviet flight had been planted.
The stories really took off in 1959 as Americans looked for evidence of the Soviet equivalent of NASA and its Mercury astronauts. There was little question that the Soviets had a space program, but details came through questionable and unofficial channels - hearsay at industry events and in casual conversations at cocktail parties.
A sketchy picture emerged of a Soviet space program with three World War II veterans named Belokonev, Kachur, and Grachev training as cosmonauts; a fourth cosmonaut, unnamed, was rumored to have been killed in a training accident.
That lost cosmonaut trainee reappeared in the following months. A two-page article titled "Flights to High Altitudes" in the Russian weekly photo magazine Ogonyok showed images of doctors, technicians, and subjects testing life support equipment. That there were three men - in fact the real Belokonev, Kachur, and Grachev - and not four seemed to solidify the existence of a lost fourth man. That they weren't cosmonauts didn't matter. Western reporters treated them as the real thing and assumed the pictures showed their actual training facilities.