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.