The Dyatlov Pass Incident saw the mysterious deaths of nine young skiers in confusing states of undress, severely injured, and with missing body parts.

On Jan. 23, 1959, nine capable skiers from the Soviet Union’s Ural Polytechnical Institute went on an adventurous hiking trip in the Northern Ural Mountains. They were never seen alive again.

Only photographs of their final days, a confounding scene at their campsite, and yet unexplained autopsy results were left behind. The Dyatlov Pass Incident has since become a plentiful source of conspiracies which range from government secrecy to paranormal phenomena — and with good reason.

Now, Russian officials have reopened the bizarre case as “Relatives, the media and the public still ask prosecutors to determine the truth and don’t hide their suspicions that something was hidden from them,” reported Alexander Kurennoi, the official representative of Russia’s Prosecutor General to CNN.

60 years ago, fifth-year student Igor Dyatlov led seven young men and two women on an expedition to cover 190 miles in 16 days across the North Ural’s Otorten and Kholat Syakhl mountains. They intended to reach a village called Vizhay from where they would make contact via telegram to conclude their journey.

Of course, that never happened, and a search party for the missing group embarked on Feb. 20. What the party found six days later baffled them: a sliced open tent and the nearly completely naked bodies of Yuri Doroshenko and Yuri Krivonischenko over a mile away. Three more skiers were found a few days later, including Dyatlov — the other four were discovered two months later when the snow had melted.

Some of the hikers had suffered chest fractures so immense that only a car crash could compare to the force of the injury. One of the women was missing her tongue, eyes, part of her lips, and facial tissue. There was also a fragment of her skull missing.

Though a criminal case had opened at the end of February, it concluded that a “spontaneous power of nature” was the cause of death. The Soviets kept the case classified until the 1970s, which had a snowball effect on the global interest in the ominous incident.

For over half a century, investigators have continued to scratch their proverbial heads over just what exactly occurred at the Dyatlov Pass.

According to the prosecutor’s office, over 75 theories have been put forward. These range from alien abduction to murder by members of the Mansi people — a tribe for whom the mountains are spiritual and must be protected. Others suggest the event was a hoax, staged entirely in order to detract from a supposed, covert weapons testing program.

The new investigation, however, will only take three theories into account that are exclusively limited to weather-related occurrences.

“All of them are somehow connected with natural phenomena,” said Kurennoi. “Crime is out of the question. There is not a single proof, even an indirect one, to favor this version. It was either an avalanche, a snow slab or a hurricane.”

A spokesman for the prosecutor’s office for Russia’s Sverdlovsk region presented a 400-page file of original case documents and materials at a press conference this week. Next month, prosecutors are scheduled to visit the Dyatlov site itself with a crew of rescue workers and experts, including forensic professionals.

Petr Bartolomey, a friend of Dyatlov’s who attended the press conference, reported that the young man was “a wonderfully knowledgable person, an athlete, always well-prepared…One could always rely on him.”

“I can say the same for the rest of the guys, although we did not go on as many expeditions as with Igor,” he said. “I am glad that, years after, a high-level investigation is resumed to understand what exactly happened.”

Whether the renewed probe by Russian officials into the mysterious series of events in 1959 will bring us closer to the truth is yet unclear. There is no doubt, however, that anything resembling clear-cut answers to the strange occurrences have yet been put forward.

After reading about Russian official reopening the investigation into the Dyatlov Pass Incident, read about the cannibal couple accused of eating up to 30 people in Russia. Then, read about the solar observatory in New Mexico reopening amid speculation that aliens caused its closure.