Ukrainian film director Oleg Sentsov gestures from a defendant's box as he attends a court hearing in Rostov-on-Don, Russia, on July 21, 2015. REUTERS/Sergey Pivovarov

It's an honor that comes with a heavy dose of irony — PEN America just awarded its Barbey Freedom to Write Award to the acclaimed Ukrainian writer and filmmaker Oleg Sentsov, imprisoned in Russia.

Sentsov, a filmmaker, has been an outspoken critic of Russia's intervention in Ukraine. He joins a distinguished list of other imperiled honorees, including Khadija Ismayilova, an Azerbaijani journalist arrested after producing a series of investigative scoops about government corruption, and Ilham Tohti, an imprisoned Chinese economist and scholar of Uighur issues. (Thirty-seven of the 40 Freedom to Write Award winners have been released from prison within 18 months of their award.)

"He's been forced to sacrifice this promising career in film because of his decision to speak out," said Suzanne Nossel, executive director of PEN America. "It's just a very vivid illustration of the intolerance of dissent by Putin's government."

Sentsov has no formal training in cinema. His first full-length film came, instead, from a passion for competitive eSports gaming. He organized several tournaments in his home town of Simferopol, on the Crimean Peninsula, and even ran an Internet cafe. When that business began to falter, he began pursuing another interest: film. He had "so many ideas for films in his head that it was impossible to keep them there," he told one friend.

So he traveled to the Ukrainian capital, Kiev, to persuade Olga Zhurzhenko, a student at the Kiev National I.K. Karpenko-Kary University of Theater, Cinema and Television, to help him make "Gamer," the story of a young man who hopes to escape his impoverished life by winning an eSport tournament.

To fund the film, Sentsov sold his car and Internet cafe. The crew consisted of just five amateurs. That was, to Sentsov's mind, an asset. "Oleg wanted the characters the actors create on the screen to be 'real.' When actors have something in common with their characters, when they are not limited with acting rules and principles — then they stay on screen the same people they are in real life," Anastasiya Chorna, an actress in the film, explained.

The movie was well-received by critics, and Sentsov had begun work on a second feature. Then Russia intervened in Crimea. And Sentsov abandoned his latest project to coordinate relief efforts for Ukrainian soldiers trapped in their base by Russian troops.

He was arrested in 2014 and charged with planning a terrorist attack in Crimea after the territory was annexed by Russia. Russian officials accused Sentsov of setting fire to the offices of a political party in Crimea and of trying to blow up a Lenin statue.

The filmmaker vociferously denied the charges and said he was tortured in prison; he had the bruises to prove it. But investigators dismissed the marks as the the result of a supposed penchant for sadomasochistic sex. The main witness recanted his claims in the courtroom, telling onlookers that evidence was extracted under torture.

Even so, after a quick trial (described by Amnesty International as "redolent of Stalinist-era show trials"), he was sentenced to 20 years in prison. His co-defendant received a 10-year sentence. Defiant, Sentsov wore a "Glory to Ukraine" T-shirt in court. When the pair heard the news, they began singing the national anthem of Ukraine.

"When they put a bag on your head, beat you up a bit, half an hour later you’re ready to go back on all your beliefs, implicate yourself in whatever they ask, implicate others, just to stop them beating you. I don’t know what your beliefs can possibly be worth if you are not ready to suffer or die for them," he said at the time. "I am not going to beg for leniency. Everything is already clear. A court of occupiers cannot be just by definition."

Experts say the harsh trial was meant to send a message that dissent in Crimea will not be tolerated. At least 10 other Ukrainians are serving sentences for similar offences.

Sentsov is currently serving his sentence in a Siberian penal colony. In a letter smuggled out of prison, he said his spirit has not been broken. He has declined visits from his wife and children (12 and 13) and allegedly refused any special treatment. In his letter, he wrote:

"For three years I’ve been sitting in a Russian prison. For those three years a war has been conducted against my country. Here, in captivity, we are limited: and not even by freedom — this can no longer be taken — but by being of little help to our country while we’re in here. To be more precise, we can do one thing: hold on. There is no need to pull us out of here at all costs. This wouldn’t bring victory any closer. Yet using us as a weapon against the enemy will. You must know: we are not your weak point. If we’re supposed to become the nails in the coffin of a tyrant, I’d like to become one of those nails. Just know that this particular one will not bend."