All it took was one hard drive for Sergei Savelyev, a soft-spoken Belarusian graduate, to take his revenge on a Russian prison system where inmates are routinely sexually abused and tortured.
Mr Savelyev was serving a seven year sentence for drug trafficking when he was put in charge of the computer system at the prison in the western Russian city of Saratov.
For two years, he would download videos showing prisoners abusing or raping fellow inmates at the behest of authorities. The videos had allegedly been stored to use for blackmail.
The clips he had to watch were gut-churning: naked men were tied to a bed and violated with a stick.
“I thought about this all the time: that I might end up in their place,” Mr Savelyev told The Telegraph in a telephone interview from exile in France. “This fear is always with you.”a
Watch: Russia investigates prison torture videos
Russian NGO Gulagu.net this month released footage as part of an unprecedented leak that documented torture across the Russian prison system.
The evidence of endemic torture was so strong that Russian authorities fired Saratov’s top prison officials and launched a sweeping investigation into the reports. It was only last week that Gulagu.net identified the man behind the leak.
Mr Savelyev, a 31-year old Belarusian who studied food safety in his hometown of Minsk before moving to Russia for a summer job, saw both sides of the system. He denies the trafficking charges against him and says he was viciously beaten and choked when he was first detained.
In 2016, he ended up at the tuberculosis ward of the Saratov prison colony, a notorious jail he had already heard about from former inmates.
On his second day on the ward, a prison official went around asking if there were people with computer skills to help run their IT system.
“After all the violence and filth you have seen throughout the investigation, the trial… those overcrowded cells with plaster crumbling from the ceiling, all the disgusting insects, they were offering me an office job. Of course, I said ‘yes’.”
Mr Savelyev knew the inner workings of the Saratov prison so well he was able to smuggle out the hard drive when he was released. He would not say how.
Gulagu.net, which is still going through the trove of video files, has already shared the footage with the Council of Europe’s anti-torture committee and is preparing to send the files to the U.N.
Mr Savelyev, dubbed “Belarusian Snowden” by the media, brushes off the comparison to the American intelligence consultant who leaked highly classified data from the NSA before fleeing the U.S. and ending up in Russia.
“Snowden escaped from a democratic country to a dictatorship. I, on the contrary, fled a totalitarian regime to a democracy.”
Watch: Alexei Navalny says Russian prison has changed his status to 'terrorist'