Maxim Zmeyev / Reuters Igor Strelkov, commander of the separatist Donetsk People's Republic militia.

SLOVYANSK, Ukraine — The men with guns came for Alexei Pichko in mid-afternoon, before the usual evening barrage of shells flew over this decrepit suburb of dilapidated shacks and half-burnt houses. When his mother went to look for him at the rebel headquarters in the security services building, they told her he was under arrest, but alive and well. One month later, the men who took him have fled their stronghold in this sleepy east Ukrainian town, unable to sustain the Ukrainian army's barrage of mortar fire, and retreated to Donetsk, the provincial capital. The building where he was held captive is now half-destroyed, lined with mulch and detritus. The only evidence of what has happened to him is on files found lying on the floor, coated in a thick film of dust, signed and stamped by the separatists' feared commander. "By order of the military-field tribunal of the [Donetsk People's Republic] militia on 17.06.2014," it reads, "I hereby proclaim that Aleksey Borisovich Pichko, resident of the city of Slovyansk, is sentenced for looting to an exceptional measure of punishment — execution by firing squad — on the basis of the Decree of the Supreme Soviet of the USSR 'on martial law' from June 22nd, 1941." "The sentence has been carried out." The three-month struggle for Slovyansk — which became the stronghold of the self-proclaimed Donetsk People's Republic when armed men seized it in April — has made the once-nondescript town of 119,000 all but unrecognizable. Buildings are smashed across town. Half the population fled. Those without the means to do so turned on each other, deprived of electricity, running water, and contact with the outside world. Detailed transcripts from Pichko's case and two other tribunals, however, appear to show how the militia's enigmatic commander, a former Russian intelligence officer known by the nom de guerre of Igor Strelkov, kept order in the city through summary wartime justice. Theft was prosecuted under a decree devised by Stalin at the start of World War II. Trials were held summarily under the jurisdiction of men known by nicknames like Nose, Gray-Hair, and Baloo. Punishments were carried out "ruthlessly and decisively."

Max Seddon / BuzzFeed Maria Pichko outside her home in Slovyansk.

The inner workings of the Donetsk People's Republic are largely a mystery. Rebel leaders often make contradictory claims about which one of them is in charge. Armed groups with apparently conflicting loyalties have attacked each other. The groups' political leaders sometimes disappear to Moscow for days at a time for vague "consultations" with Russian political figures. (Ukraine and its Western allies say the Kremlin is stage-managing the conflict, charges Moscow angrily denies). But the documents — found by BuzzFeed and two other reporters on the floor of the security services building (and corroborated by sources including a man who stood "trial") — indicate Strelkov enjoyed at least some degree of autonomy in running Slovyansk. Nothing in them links the rebels directly to Russia. Instead, Strelkov, whose real name is Igor Girkin, appears to have improvised his own justice system, based on Soviet wartime nostalgia and a need to keep the local population in check. Written testimony from the accused and witnesses is made out to Strelkov. The execution orders are signed and stamped by him. Miroslav Rudenko, a spokesperson for Strelkov, said that the rebels in Slovyansk had carried out multiple tribunals for looting — including one first publicized in May and detailed in the files — under the decree, issued on the day Nazi Germany invaded the Soviet Union. "We needed a military legal basis to prosecute looting and similar wartime phenomena effectively, so we turned to history for an example," he said. A local man arrested for treason, Alexander Pirozhenko, confirmed an account given in another set of documents of his trial, which the rebels held under Ukrainian law. Pirozhenko was held for eight days on charges of shining a flashlight in order to betray rebel positions, which were dismissed for a lack of evidence.

Max Seddon / BuzzFeed Strelkov's order to execute Pichko.

Pichko's case, however, shows Strelkov involved himself in even petty crime cases with no connection to the militia. An unemployed welder recently released from prison after four and a half years served for stealing a phone, Pichko, 30, had intended to move to Moscow to work as a laborer but got stuck in Slovyansk when the conflict broke out. Though he told his mother he had found odd jobs around town, he wrote in a confession that he found no work apart from standing around at rebel-built barricades. Neighbors standing on the dirt road where Pichko was arrested in the run-down suburb of Krasny Molochar claimed Pichko regularly committed burglaries during regular drinking bouts. "He was bad from the day he was born," a middle-aged man said. (He and nearly all the other local residents declined to give their names, fearful of both the Ukrainian army and the separatists.) According to the confession, Pichko got drunk on June 14 with a friend and a local man he had just met on the street. After noticing a house whose owner had fled the suburb to escape the conflict six weeks earlier, Pichko broke in through a window to steal two shirts and one pair of pants. Neighbors then ran to find the nearest militiamen, who arrested him a few hours later. The next day, a rebel nicknamed "Lawyer" inspected the house with two armed men from the nearest checkpoint. He filed a detailed report including a blueprint and several photographs. The armed men interrogated several witnesses, who testified that Pichko burglarized the house with his two friends.

Max Seddon / BuzzFeed Pichko's confession.