At first glance, the prisoner swap between the Ukrainian government and pro-Russian separatists appeared fair enough: On a deserted stretch of highway along the front line, each side released 28 captives, observing a principle of numerical parity.
Under the watchful eyes of mediators from the Organization for Security and Cooperation in Europe, the prisoners walked past one another to freedom.
Then the questions started to pop up. The pro-Russian separatists — who with the aid of the Russian Army routed the Ukrainians in battles in August, taking many captives — released men appearing to be actual prisoners of war.
The Ukrainians, however, widely understood to be lacking enough prisoners of their own to effect a one-for-one exchange, set free a motley group of men, women and teenagers wearing tracksuits or dirty jeans, and taken, they said, from jails as far away as Kiev.
Soon enough, many of them were objecting to anybody who would listen there on the highway that they had never fought for pro-Russian separatists, and in fact had no idea how they ended up in a prisoner exchange in eastern Ukraine.
“I am a civilian and I was included just to fill out the numbers,” Nikita Podikov, 17, said in an interview. Ukrainian soldiers arrested him in a town near the front lines two weeks ago as they pulled back during a retreat, he said.
Mr. Podikov said the authorities accused him of belonging to a gang of pro-Russian assassins working behind enemy lines, but never gave any proof. “I never fought, I never killed anybody,” he said.
“They arrested me, beat me for two days and then kept me for trading,” he said. On Sunday, he wound up in a prisoner swap of 27 men and one woman, only seven of whom were rebel fighters.
In interviews at their point of release and in a dormitory where former detainees are housed in Donetsk, a dozen men freed in exchanges over the weekend by the Ukrainian Army gave similar accounts.
Some said they were arrested months ago in other parts of Ukraine for pro-Russian political actions, such as joining protests calling for autonomy in eastern Ukraine or for distributing leaflets.