When you posted the part about the chest injuries it reminded me of the Dyatlov Pass incident that was posted in the Unsolved Mysteries thread: http://en.wikipedia.org/wiki/Dyatlov_pass_accident
Wikipedia posted:
and both Dubunina and Zolotarev had major chest fractures. The force required to cause such damage would have been extremely high, with one expert comparing it to the force of a car crash.Notably, the bodies had no external wounds, as if they were crippled by a high level of pressure. One woman was found to be missing her tongue.[1]
After looking a little further, I found this picture - taken a day before the incident.











