Unexplained and bizarre death of 9 Russians.

I just stumbled across the fascinating tale of the Dyatlov Pass Accident. The case is full of bizarre findings. Nine hikers set out into the wilderness and were never seen alive again. Their bodies were found in groups a good distance from their camp, all in little more than underwear, as if they had to flee their tent in a hurry. Their tent was ripped open from the inside, like they didn’t even have time to use the tent’s door. Five of the hikers showed no signs of trauma and likely died from hypothermia — two of which were found around a temporary fire that they made while in their underwear. None of them seemed to dare to return to the tent. The other four hikers died of internal injuries but showed no external wounds, one from a fractured skull, and two from fractured chests, as if they had been crippled by extreme pressure.
Here are some more facts of the case (from the Wikipedia article):

• Six of the group members died of hypothermia and three of fatal injuries.
• There were no indications of other people nearby apart from the nine travellers on Kholat Syakhl, nor anyone in the surrounding areas.
• The tent had been ripped from within.
• The victims had died 6 to 8 hours after their last meal.
• Traces from the camp showed that all group members (including those who were found injured) left the camp of their own accord, by foot. This implies that those with injuries were injured after they left the camp.
• The fatal injuries of the three bodies could not have been caused by another human being.
• Forensic radiation tests had shown high doses of radioactive contamination on the clothes of a few victims. These test results were not taken into account for the final verdict.

The only footprints found in the snow were those of the hikers, so it couldn’t have been caused by any sort of land animal, human or otherwise. There were no traces of an avalanche. The most curious part of the case is the high level of radioactivity found in the bodies. The families who attended to the burial procedures reported that the corpses’ skin that had turned orange and hair that had turned gray. None of the Russian military helicopter pilots would transport the corpses, not even in body bags. Did they know more than they let on?
The case was never solved. So what in the hell caused this accident? The Wikipedia article vaguely mentions aliens, but of course all people ruled it out....I am looking in to this at the moment...If you have details let me know.