Videos Suggest Captive Russian Soldiers Were Killed at Close Range

Iva Vukusic, a war crimes prosecution expert at Utrecht University, said that it was difficult to determine whether a war crime had or had not been committed based on the video evidence alone, and that the critical factor was time — when the Russians were shot.

“Was it in one or two bursts of fire at the moment of, or immediately after, the last Russian comes out and shoots at the Ukrainians?” Dr. Vukusic said. “Or was it after the immediate threat had been neutralized, as an act of revenge — then this is more clearly a war crime.”

If the Russians were shot in the heat of the moment, Dr. Vukusic said, it is not clearly a crime.

“If these P.O.W.s were not searched yet, then the Ukrainians don’t know if they’re armed, even if they are on the ground.”

The Russian gunman’s actions are critical, too, Dr. Vukusic said, and could be deemed perfidy — feigning surrender or noncombatant status as a ruse against the Ukrainians — which may be prosecutable as a war crime under the Geneva Conventions.

“It may very well be that, had this guy not fired, that they all would have been captured as P.O.W.s, and survived,” Dr. Vukusic added.

United Nations investigators said last month that they had documented cases of Russian forces torturing civilian and military prisoners. The investigators also found that Ukrainian troops had tortured and abused prisoners of war, but “on a lesser scale.”

The Times has reported on multiple cases of alleged Russian war crimes, including the use of banned weapons, attacks on civilian targets and the killing of noncombatants. In March, a visual investigation by The Times showed Russian troops executing a group of captive Ukrainian fighters and a civilian in Bucha, a suburb west of Kyiv. The Times also reported on the alleged execution of Russian captives by Ukrainian forces in April.

The footage caused an outrage among Russian pro-‌war commentators. Vladlen Tatarsky, a popular activist and blogger, said in a post on the Telegram social messaging app that every Russian “must watch this several times to understand whom we are fighting against” and that “not a single Russian can live and sleep calmly” as long as the perpetrators are alive.

In its Friday night news show, Channel One, Russia’s state television network, said that the videos were proof that the Kyiv government was committing war crimes. It featured Vladimir Kornilov, a political scientist, who said that “Ukraine is never accused of war crimes because they kill the Russians.” A report by Rossiya-1, another state network, accused the West of keeping “organized silence” over Ukrainian war crimes.

Russia’s human rights council said it would send the video to international organizations. The country’s investigative committee, Russia’s equivalent of the F.B.I., opened a criminal investigation into the encounter.

Dr. Vukusic, the war crimes expert, said that the International Criminal Court’s Prosecutor was most likely examining the episode, given the attention it has received. She said that an investigation would require a site visit to establish where everyone was and to collect bullet casings, pathological and forensic examinations of recovered bodies, and to scrutinize the Ukrainian unit’s actions after the shooting.

Dr. Vukusic said that in assessing the case, investigators might examine if the Ukrainian unit had a pattern of such behavior, which group of soldiers was outnumbered and by how much, and if other forces had been nearby, and whose forces.

The Ukrainian authorities have the ability to investigate and should share their evidence and findings transparently, Dr. Vukusic said.

“They should seize on this opportunity and send a message: ‘We do not want a dirty war. We want to fight with honor, and legally.’”

Reporting was contributed by Ivan Nechepurenko Cassandra Vinograd, Marc Santora and Dmitriy Khavin. Videos were produced by Taylor Turner and Chevaz Clarke-Williams.