RFE/RL has determined the identities of and new details about seven of the nine men who served on so-called "military tribunals" and carried out several executions of those it "convicted" in the eastern Ukrainian city of Slovyansk.

Documents obtained by RFE/RL, outlined in an exposé published on July 23, show how the fates of several men were decided by the "tribunals," established by Igor Girkin, a former Russian intelligence officer better known by his nom de guerre Igor Strelkov, on the basis of a draconian law conceived by dictator Josef Stalin and imposed shortly after Germany invaded the Soviet Union in World War II.

The investigation is based on documents recovered from Girkin’s former office at the city’s security service headquarters, open-source research, and interviews with alleged torture victims, witnesses, and family members of the victims.

On top of identifying the nine men who served on the tribunals along with Girkin, RFE/RL has found that one of them is tied through a Moscow-based organization for Russia-backed fighters to Vladislav Surkov, one of Russian President Vladimir Putin’s closest aides at the time and the architect of the Kremlin’s Ukraine policy.

Girkin was a key commander in the Russia-backed separatist forces in the early stages of the war against Ukrainian government troops that has killed more than 13,200 civilians and combatants since April 2014.

Ukraine's government has called Girkin a Russian agent and accused him of war crimes. He resigned as a rebel commander in August 2014 amid reports that he had been wounded in battle.

Girkin is one of four defendants charged with murder by Dutch prosecutors for their alleged roles in the July 17, 2014, shoot-down of Malaysia Airlines flight MH17 over the battlefields of eastern Ukraine, which killed all 298 people on board.

The new information uncovered by RFE/RL about the tribunals and those who meted out its sentences weaves another layer of evidence into the fabric of what experts believe may constitute war crimes by Russia and the separatists it backs with soldiers, weapons, money, and political support in the conflict.

The revelations also come as Kyiv pursues justice through cases in Ukrainian courts and legal claims against the Russian state in the European Court of Human Rights (ECHR) and International Criminal Court (ICC).