The investigators quickly came to the conclusion that locals and hunters weren't involved in the tragedy. As well as there were no «strangers» next to the accident site. The hunters Anyamov and Sheshkin who saw the traces of «narrow» skis of Dyatlov’s group on the Auspia definitely said that they would know if there was someone. According to the evidences of hunters (in particular, Cheglakov and Pashin) when Dyatlov's group went along Auspia river they were following a hunter-mansi footprints who was trailing an elk. But then approximately at a distance of 10 km from the place of the accident they went separate ways – the hunter went aside following the elk’s trace and Dyatlov's group went further along the river.

Hunters and locals couldn't tell anything certain regarding the causes of the group death. But everyone pointed to the danger of strong winds on an open woodless top of mountain ridges. They noticed that on the ridge hurricane force wind is capable to freeze a person for a very short time if one cannot take a shelter in woods, in a hollow, i.e. in the place protected from wind. A forester Pashin said that when such winds were blowing he had to wait in the hollows up to 6 days being warmed by the fire. The hunters mentioned that the hurricane force wind could blow within 10 days and more atop, and some old residents noted that they knew the cases when people died from a strong wind in the local mountains. Ryazhnev, Dryakhlykh, Popov and others witnessed that at the beginning of February they observed unusually strong winds and frosts under 30 degrees. Therefore according to evidences of the locals wind played a fatal role in this accident especially taking into account visible causes of Dyatlov’s team death from freezing.

The investigation hasn’t found any objects by which Dyatlov’s group has been injured in such a strange way; nothing in particular didn't help to identify their cause. They failed to discover the place where the injuries have been made: atop, near the tent, on the slope or down in the woods. Vozrojdenniy has concluded that Dubinina could live no more than 10–20 minutes having her heart injured and this seemed to exclude the possibility of receiving any injuries in the tent zone. In fact, 8 or 9 pairs of footprints going down have been found, but it seemed obvious that Thibaut, Dubinina and Zolotaryov couldn't walk down injured like this. They also didn’t find if the wounded were being carried or transported. The slope near the tent was not steep, from 15 to 20 degrees, by different estimates, and a snow like a hard crust didn't suggest that there was a possibility of avalanche descending on the tent. Well, no trace of an avalanche on the slope was found. Although anyone was not looking for this trace thinking that the slope is insufficiently abrupt.

In addition the investigation found that members of Dyatlov’s team died approximately 6–8 hours after the last meal. Three watches out of four on their wrists showed close time: Slobodin-8.45, Thibaut – 8.14 and 8.39 (he had two watches), and Dyatlov’s watch showed 5.31. According to the practice of rescue operations the watches usually stop on a hard frost approximately one hour after the death of the person. But it doesn’t always happen. Nevertheless the watches stop time showed that Dyatlov’s team were lost about 7.00-8.00 in the morning on February, 2th.

The funerals of three victims took place on May 12 on the Mikhaylovskoye cemetery and Zolotaryov was buried later on the Ivanovskoye cemetery next to Krivonishenko.

Lev Nikitich Ivanov, the investigator of the prosecutor's office who conducted the case of Dyatlov’s group couldn't find an explanation for the causes of the accident. He could not overcome contradictions, connect the known facts and construct a scene of the accident.

In the case one can certainly notice a few «lines» that the investigators developed in order to make up different versions based on different assumptions. Such was a line checking absence or presence of outsiders on the Tragedy place, including, first of all, local residents. Such was a line checking actions of the leader relating to compliance of expedition arrangement and actions en route. As well as checking of absence of some nonlegal and conflict behaviour of Dyatlov's group that could result in the accident during expedition. It is important to understand that all these lines have been checked but they gave a negative result, that is why assumptions that created them didn't become «working drafts» of Dyatlov's accident. At the same time other «lines» of the investigation were not «completed» because of lack of information that the investigators didn't have access to or couldn't find. For example, there was incomplete data about meteorological situation on the Tragedy day, launches of missiles and nuclear tests on Novaya Zemlya. Of course, considerable part of information was not available and it was very difficult or impossible to obtain it those years.

Having studied the evidences of several witnesses (of meteorologist Tokareva about «fiery sphere» flight observed on February 17, the evidences of Atmanaki, Karelin, militaries Savkin, Anisimov, Malik, Novikov, witness Skorykh and evidences of other searchers about viewing of «fiery spheres» on March 31) Ivanov started to assume that the accident with Dyatlov’s group could be connected with some kind of «experiments». He tried to understand the nature of those «experiments», visited the place of the accident once again and investigated the woods. In one place he noticed that branches of fir-trees were scorched. A strange skin color of the victims also evoked some suspicion. That’s why Ivanov decided to make an expert examination and investigate bodies and belongings of victims for radiation. These are his words written down by the journalist Bogomolov for the article «Secret of fiery spheres», a newspaper "Lenin way", Kustanai, of November 22 and 24, 1990: «…Having agreed with the scientists of UFAN (Ural branch of Academy of Sciences of the USSR) I carried out very extensive research of clothes and different body organs of the victims for the presence of «radiation». Besides we made the comparison with clothes and internal of the people who were killed in the car accidents or died a natural death. The results turned out to be surprising. The non-specialists will not be able to understand the analysis results but I will mention only the following ones: the brown jersey of one tourist who had bodily injuries showed 9900 disintegrations per minute, and after the sample has been washed – 5200 disintegrations, i.e. these data point to the radioactive «mud» which could be washed off. It has to be said that before these corpses were found they were intensely washed by meltwater under the snow – actually there were rivers. Therefore at the moment the tourist has died the radioactive «mud» was many times more…". "…When I reported Eshtokin on my findings, fiery spheres and radioactivity, he gave me absolutely explicit instruction: everything to be classified, sealed up, and handed over to a special service and for me to forget about it all. It is needless to say that I executed this order to the letter…»

As a result of all these actions the case was closed by date of resolution on its extension till May 28, 1959. After having been checked in Moscow by the USSR prosecutor's office the criminal case was returned on July 11, 1959, and according to the order of Klinov, the prosecutor of Sverdlovsk, for some time it was kept in the confidential archives (pages 370–378 of the "criminal case" were handed over to the top secret archive). But then it was declassified and handed over to the archives of Sverdlovsk region. There were all indications that Klinov's instructions to Lukin, a head of investigation department in the prosecutor’s office, and to Ivanov, the subordinate of Lukin, to classify the case, were a direct consequence of that Eshtokin's order Ivanov mentioned (and in the beginning of investigation A.P. Kirilenko's instructions not to disclose the facts). After all it is clear that Ivanov reported about progress of the case both to Klinov and Eshtokin. He couldn't «ignore» Eshtokin’s and Kirilenko's instructions as well as he couldn’t hand over them to Klinov as they were orders both for Ivanov and for Klinov. And Klinov followed the order of the second secretary of regional committee to classify the case. It is evident that Eshtokin's decision was based on the information provided by Ivanov. Obviously he had no other information. After having checked the case the prosecutor's office of RSFSR (the Russian Soviet Federated Socialist Republic) didn't report any new information and didn't give any instructions to classify the case.

Trying to classify the materials of the case the authorities wanted to hide the information which could be a source of various gossips and, first of all, to suppress the facts about «fiery spheres» and results of radiation analysis. After all such gossips somehow accused authorities that the causes of the accident weren’t still found. The main argument for case was lack of elements of crime. The investigation hasn’t found any direct evidences of crime and they also couldn’t make any certain conclusions on causes of death of the tourists. The results of investigation were limited by the description of events of the accident and represented an ambiguous statement that «death of tourists was caused by force majeure circumstances». But in the description the investigation didn't specify what kind of «force» it could be and the course of events of the accident.

For some years the authorities didn't allow the organized tourist groups to visit the accident site. But several tourists without official route request visited the place of accident trying to find new evidences and a key to an accident. The first organized group (Valya and Toma Yakovenko, Yura Yudin, Zhora Kuntsevich, Sasha Danilin, Volodya Andrushechkin, Olya Khvatkova, Ira Tkachenko) visited the place of Tragedy in August 1963 and on the island hill fixed up a memorial gravestone made by a sculptor A.F. Karas upon the project of Gennadiy Ptitsyn and Yakov Ruvimov.

And right at the beginning of the article Ivanov made a conclusion: «…True causes of death were kept from people, just a few persons knew about them: the former first secretary of regional committee A.P. Kirilenko, the second secretary of regional committee A.F. Eshtokin, prosecutor of the region N.I. Klinov and the author of these lines, who were engaged in a legal investigation. At the moment neither Kirilenko nor Eshtoknn nor Klinov are not alive…».

Pictures from cameras and belongings of Dyatlov’s team made it through to the investigator Ivanov, and after their studying Ivanov allowed Vadim Brusnitsin and Yury Yudin assisted by Boris Bychkov and Evgeny Chubarev to make photos for victims relatives. So there were "photo albums" about Dyatlov’s group which belonged to the families, searchers and case investigators. Over time they were also «added» by pictures from the previous campaigns of Dyatlov’s group and pictures of participants of the search. The photos in the albums were mixed as for time and place. There was no «privacy» in procedures regarding pictures. In 2009 L.N. Ivanov’s daughter handed over the films she kept to the «Dyatlov’s group Fund» (Fund of Dyatlovtsev) to the investigation volunteers Yu.K. Kuntsevich and A.A. Koskin. Some of these pictures can be seen here. In the belongings of Dyatlov’s group there were found 4 cameras which were given back to the relatives of victims, but numbers of all cameras and their owners are known from materials of volume 2 of the case.

A. Mokhov and Buyanov are standing at the memorial gravestone in the island hill of Dyatlov pass in August 2008

25 years after termination the case of Dyatlov’s group death could be erased "under the normal procedure" according to retention period. But the prosecutor of the region Tuykov instructed not to erase a case like "socially significant". Therefore it was kept safe in the archives of Sverdlovsk region and remained intact.

A chronology of searching works (? – the dates cannot be defined exactly):

23.02–05.03 – Slobtsov’s group (from 27.03 – master of sports Maslennikov, a leader of composite group of Slobtsov-Karelin-Chernyshov+Moiseev and Mostovoy with dogs);

27.02–10.03 – Karelin’s group

1.03.59 – (12.03?) – Akselrod-Sogrin’s group.

3.03 – 8.03 – a group of masters Bardin, Baskin and Shuleshko from Moscow (Shuleshko left on March, 9).

7.03 – (17.03?) – A.K. Kikoin’s group (alpinists from UPI)

12.03 (?) – 23.03 – the first group of Martushev.

?.03 —?.03 – a group of military students from Ivdellag NCO school under the direction of senior lieutenant Potapov – 10 students.

?.03 —?.03 – a group of sappers with mine detectors under the direction of lieutenant Shestopalov – 7 sappers.

?.03 —?.04 – a group of sappers of railway troops under the direction of lieutenant Avenburg;

25.03–06.04 – Sogrin’s group;

06.04–17.04 – the second group of Martushev;

17.04–25.04 – Blinov’s group (the relocation of the camp from Auspia to Lozva from April 19 till 22.04.59);

25.04–07.05 – a group of Askinadzi and Nicolay Kuznetsov (till the end of the rescue operation and camp evacuation).