And they haven’t discovered the secret Yeti?
A Yeti wouldn’t not have caused high levels of radiation.
Nor would the Mansi.
The military or Space invaders could have though.
I tend to believe the soviet military story as being the more correct one.
By 1959 Soviet research into radiation had taken a back seat to biological weapons research. Perhaps they’d gone into a remote area to try LSD, and, uh, took a little too much.
http://en.wikipedia.org/wiki/LSD