This past summer, Dmitry Ostryakov, a high school astronomy teacher and human rights activist, drove for nearly 16-hours from his home in St. Petersburg to the village of Gotovye near Russia’s border with Ukraine.

His father joined him for what was a deeply personal journey. His great-grandfather, Vasily Ostryakov, lived in the village during World War II and was then convicted there, on charges of collaborating with the Nazis. And for several years now, Ostryakov has been trying to uncover the full story — and whether he was really guilty, or not.

But what started as an interest in his family history has turned into an extraordinary battle with the Russian authorities, who refuse to release the criminal case files they hold on Vasily Ostryakov, even though they are now more than 70 years old. Dmitry Ostryakov has come up hard against what critics characterize as the government’s determination to bury anything that conflicts with its glorious version of Russia’s past.

The cornerstone of this narrative is the Soviet Union’s victory over Nazi Germany when Joseph Stalin was leader. And in stressing that victory, many say the mass killings and political terror he is also famous for are being deliberately played down. Russia’s President Vladimir Putin has all but admitted it, warning in an interview earlier this year that “excessive demonization” of Stalin was being used as a way to attack Russia.

The files are held by the FSB, Russia’s domestic security agency, and the courts have repeatedly taken its side against Ostryakov. In Kafkaesque fashion, Russian law says that the documents can only be shown to parties involved in the criminal case — which was in 1943. It was the NKVD, Stalin’s secret police, who opened the case. The files were then inherited by its successor, the KGB, and then in turn by its post-Soviet successor, the FSB.

Dmitry Ostryakov has been interested in his family history since he was 10 years old. But the now 33-year-old teacher knows little about his great-grandfather’s fate other than that he was convicted of Nazi collaboration after the Red Army retook Gotovye. He was then sentenced to seven years in a Gulag prison camp, in Russia’s Far East, and died there just 18 months later. Vasily Ostryakov has no known grave.

“I would just like to know the details of this case,” says Dmitry Ostryakov, who has also investigated other branches of his family’s history. “Did my great-grandfather collaborate in forms that I find acceptable, or not?” Russia’s President Vladimir Putin warned in an interview earlier this year that “excessive demonization” of Stalin was being used as a way to attack Russia.

There is a “myth that there were only heroic people during the war and that we only need to talk about them,” says Ostryakov. “But it wasn’t like that. There were different people, different human stories, different situations.”

The courts have backed the FSB’s circular argument that such files can only be shown to parties to the criminal case.

An exception can be made for relatives if the individual in question was rehabilitated — a legal procedure introduced after the end of the Soviet Union for victims of Stalin’s repression. And Dmitry Ostryakov tried that approach. But in 2015, a court in Belgorod, the main city in the region where his great-grandfather lived, threw out his petition.

There are no definite figures on the number of people who have not been granted rehabilitation, but Ostryakov says it is likely to run to hundreds of thousands.

The little information he does have about his great-grandfather is from a short document handed to him in 2015 by prosecutors. Vasily Ostryakov, born in 1897, worked as a secretary for a local collective farm in Belgorod region for the six months it was under Nazi control from July 1942. In his trial, he pleaded not guilty of collaboration and said he was elected to the role and because he was trusted by fellow villagers.

“He was an ordinary peasant,” says Dmitry Ostryakov. “He was a civilian who worked as an intermediary between the occupying power and the local population.”

And in Dmitry Ostryakov’s view, the fact his relatives were able to live in the same village for years after his death without being shunned by locals, suggests his great-grandfather did nothing wrong. But he admits he is speculating. This is “fantasy,” Ostryakov says. “In order to speak more objectively I want to see the criminal case materials.”

When Dmitry Ostryakov arrived in the village Gotovye — his first ever visit — he found his great-grandfather’s house. He also tracked down the grave of another person who was convicted of collaboration at the same time. But unlike his great-grandfather, this man served his sentence and returned to live out his days in the village.

Many thousands of people were sentenced to death, or long prison terms on flimsy or fabricated evidence during Stalin’s brutal rule. And during and after World War Two, which Russians refer to as the Great Patriotic War, those suspected of cooperating with the Nazis were treated with particular severity. That included hundreds of thousands of Soviet soldiers captured by the Nazis, who were sent to prison camps once they were liberated by the Red Army.

The situation the family now find themselves is not unusual, according to Ivan Pavlov, the head of Team 29, a Russian NGO and law firm working with Ostryakov on the case. The court rulings are in line with an “obvious trend towards secrecy” in modern Russia, he says.

After losing their bid to rehabilitate his great-grandfather, Dmitry Ostryakov and Team 29 turned to a St. Petersburg court for permission to see the documents last year. But the judge there also ruled in favor of the FSB. They are now considering taking the case to Russia’s Constitutional Court and the European Court of Human Rights.

In a small ray of light, the St. Petersburg court threw out a legal attempt by the FSB to compel Ostryakov to pay the 26,000 rubles ($434) expenses of one of its staff members who had traveled by train from Belgorod for the hearing. “I should decide whether to tell other people the story of my great-grandfather. Not the state.” Dmitry Ostryakov

But they are rowing against a strengthening tide. Several new statues to Stalin have been erected in recent years, including a bust unveiled by Russia’s Culture Minister last month. And historians and rights activists say that highlighting the Soviet dictator’s crimes, or his wartime mistakes, is becoming increasingly risky.

Those objecting publicly to the state’s preferred narrative have faced losing their jobs, or even criminal prosecution. Yuri Dmitriev, a 61-year-old historian who spent his life uncovering the mass graves of victims of Stalinist repression is currently being tried in the northern city of Petrozavodsk on charges of pedophilia, which friends and supporters say are fabricated.

Ostryakov says the publicity around his legal battle has not just generated bureaucratic brick walls, but also letters of support from people in similar situations. He wants to change the law, to give relatives of those who have not been officially “rehabilitated” access to documents about their cases.

“I should decide whether to tell other people the story of my great-grandfather,” he says. “Not the state.”