1.Evidence of the execution appeared on social media earlier on Oct. 1. The POWs were reportedly killed after surrendering on the front line near Pokrovsk. The Prosecutor General's Office said it was verifying the material published online and investigating the circumstances around the case. The execution of POWs is a "cynical and gross violation of the Geneva Conventions," the Prosecutor General's Office said.  "This is the most massive known case of execution of Ukrainian POWs on the front line," Prosecutor General Andriy Kostin said. "The murders and torture of prisoners are not an accident, but a purposeful policy of the Russian military and political leadership," he added. In early September, Russian forces executed three Ukrainian POWs near Toretsk in Donetsk Oblast. The Prosecutor General's Office said earlier this year that it was investigating more than 50 cases of execution of Ukrainian POWs.