Inside Russia’s brutal detentions of Ukrainians.

KHARKIV, Ukraine — It was a particularly dangerous time for a military-age man in Russian-occupied northern Ukraine, where Russian troops were losing ground before a ferocious Ukrainian counterattack this past spring. That was when soldiers from the occupying forces seized a young auto mechanic while he was walking in his home village with his wife and a neighbor, blindfolded him, bound his hands and shoved him into a bus.

It was the beginning of six weeks of “hell,” said Vasiliy, 37, who like most people interviewed for this article declined to give his surname for fear of reprisals. Shunted from one place of detention to another, he was beaten and repeatedly subjected to electrical shocks under interrogation, with little understanding of where he was or why he was being held.

He was far from the only one. Hundreds of Ukrainian civilians, mainly men, have gone missing in the five months of the war in Ukraine, detained by Russian troops or their proxies, held in basements, police stations and filtration camps in Russian-controlled areas of Ukraine and ending up incarcerated in Russia.

Thousands have passed through this sprawling, ad hoc screening system in the war zone, but no one knows exactly how many have been sent to Russian jails. The United Nations Human Rights Monitoring Mission in Ukraine has documented 287 cases of enforced disappearances and arbitrary detentions of civilians by Russia and says the total is almost certainly more, but probably in the hundreds, rather than the thousands.

Vasiliy is one of a small number of people detained in Russia who have returned to Ukraine. He was released after about six weeks and eventually made his way back through a long, roundabout journey after a total of three months away. Back at work in an auto repair shop in the northeastern city of Kharkiv, he said he was just glad to have survived.

“It was shaming, maddening, but I came out alive,” he said.