I want to know whether the following story is true or not:
An atheist Russian professor said that he was on a mission in Siberia when he saw, as they were excavating, a scene that he wished his head had been cut off before seeing: naked men and women burning in fire. Their voices were terrifying and their images even more so.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

We absolutely believe in the torment and the delight of the grave,  since there is evidence for that in the Quran and authentic Sunnah:

In terms of Quranic evidence:

-   Allaah The Almighty Says about the people of Pharaoh, (what means): {So Allaah protected him from the evils they plotted, and the people of Pharaoh were enveloped by the worst of punishment, the Fire, they are exposed to it morning and evening. And the Day the Hour appears [it will be said], "Make the people of Pharaoh enter the severest punishment."} [Quran 40:45, 46].  These verses expressly show that the torment and delight of the grave are true.

-   Allaah The Almighty Says (what means): {And we will surely let them taste the nearer punishment short of the greater punishment that perhaps they will repent.} [Quran 32:21] A group of scholars of Tafseer (Exegesis) said that "The nearer punishment" refers to the torment of the grave.

-   Allaah The Almighty Says (what means): {And indeed, for those who have wronged is a punishment before that, but most of them do not know.} [Quran 52:47] Many scholars of Tafseer (Exegesis) mention that "a punishment before" refers to the torment of the grave. 

-   Allaah The Almighty Says (what means): {And if you could but see when the angels take the souls of those who disbelieved... They are striking their faces and their backs and [saying], "Taste the punishment of the Burning Fire.} [Quran 8:50]

As for the evidence from the Sunnah, there is evidence that was narrated in Saheeh Al-Bukhari, Saheeh Muslim and other books of Hadeeth.

Ibn Abi Al-‘Izz, the Hanafi scholar mentioned that it should be known that the fire (torment) and the delight of the grave differ from the fire and the delight of this present life. Allaah The Exalted heats the dust and stones around the dead person until they became hotter than the firebrands of this present life, nevertheless, if a living person were to touch them, he would feel nothing. Moreover if two persons were buried together in the same grave, one of them might be in a garden of the gardens of Paradise, while the other might be in a pit of the pits of the Hell. Notwithstanding this, none of the bliss of the former person reaches the latter or vice versa. 

This is not strange since the power of Allaah The Almighty is limitless and miraculous. However, humans  are inclined to deny what they do not see with their own eyes. The manifestation of the power of Allaah in this world does exceed this, thus He may allow some of His servants to see the torment and the delight of the grave if He wills, while concealing this from the majority of His servants to maintain the rationale behind Takleef (religious duties) and belief in the unseen.

Also the Prophet, sallallaahu ‘alayhi wa sallam, drew our attention to an additional reason for concealing the torment of the grave from the majority of people: he said that had it not been for his fear that people would stop burying each other he would have supplicated to Allaah to let people hear the torment of the grave like he had heard it. [Al-Bukhari] On the other hand, animals hear and realize the torment of the grave because it does not apply to them.

With regards to the story of the Russian professor, if it was true, then it is one of the uncountable pieces of evidence that prove the truthfulness of the Prophet, sallallaahu ‘alayhi wa sallam, in what he told us about the promises and threats of Allaah The Exalted, whose power is greater than this.

However, if it was fabricated then this cannot effect our firm belief in the Quran and the authentic Sunnah; albeit there are many traditions about righteous people who have seen indications of torment and delight in the life of Al-Barzakh (the interval after death and before the Day of Resurrection).

Allaah Knows best.