Obfuscation is the default reaction to any accusation. When Malaysian Airlines Flight 17 was blown apart over eastern Ukraine by a Russian missile in 2014, the defense ministry in Moscow argued that it could have been shot down in a false-flag operation. When the poisoning of Sergei Skripal was tied to Russian agents, the foreign ministry hinted that a British laboratory was the real culprit. Most recently, parliamentarians have claimed that last summer’s protests in Moscow were orchestrated by Washington. Truth is seen as relative, and conspiracy has become the coin of the realm.

Here’s what we know about the Dyatlov Pass incident: The nine skiers, all college students, had set out from Yekaterinburg, then known by its communist name, Sverdlovsk, in January 1959, singing songs on an overnight train. They planned to ski about 200 miles over 16 days, summiting several peaks along the way, allowing enough time to be back for the spring semester. After catching a lift with some lumberjacks and following a sleigh driver north, the group skied out of an abandoned village on January 28, eventually making it to their final campsite on February 1.

Searchers later found their tracks along a frozen river, and, upon reaching Dead Mountain, stumbled across a half-collapsed tent on a steep, windswept slope. Inside, food supplies and outer clothing were laid out, as if the group had been about to cook dinner. Nine pairs of boots stood along one wall. Bizarrely, the tent appeared to have been slashed open—from within.

In the forest below, the investigators came across two bodies under a cedar tree, lying next to the remains of a fire. Although the temperature had been down to -40 degrees Fahrenheit the night the group disappeared, the pair were wearing only long underwear. Fragments of human skin on the tree revealed that they had broken off branches. The bodies of Dyatlov and two others, also without shoes and coats, were found several hundred feet away. It wasn't until the snow began to thaw two months later that the remaining four corpses were found. Two had broken ribs, and one's skull was partially crushed.

The inquiry, carried out in spring 1959, left many questions unresolved. Why did the skiers flee the tent to certain death in the wind and snow? What caused the blunt-force traumas? Why did an analysis find elevated levels of radioactivity on two of the victims' clothing? These questions were all beyond the purview of the official investigators, who, while baffled, concluded that there had been no foul play, and that the students were killed by an “elemental force that the tourists were not able to overcome.” The case was closed, and the findings were archived as “secret,” as was routine in the Soviet Union at the time.

A local journalist was barred from filing a report on the incident, and for decades the only publication related to the mystery was a novel by one of the searchers. (It had a slightly happier ending: After hurricane-force winds blow one girl down the slope and trap the others who rush to help her, the group leader attempts to return to the tent and dies. The rest find shelter in a trapper's hut.) But then came the Soviet breakup, which lifted the curtain of silence over the traumatic past. The extent of Stalin's repressions was revealed to the public, as was the existence of the Molotov-Ribbentrop Pact. Impoverished by financial collapse, and shocked that much of what they had been taught since childhood was a lie, many Russians were cast emotionally adrift. Faith healing, cults, and pyramid schemes flourished.