Videos and photos resurfaced on social media with evidence of the crimes, including drone footage showing the shooting of the POWs as they surrendered to Russian troops, as well as videos and photos with bodies of Ukrainian soldiers suggesting torture and violent death in captivity.Lubinets said that Ukrainian authorities document the cases as much as possible and pass the evidence to the Commissioner for Human Rights in the Russian Federation. "In my opinion, the main reason (for the executions) is that the Russian military does everything possible so that Russian soldiers have no desire to surrender to Ukraine," Lubinets said.Apart from that, Russians kill prisoners to demonstrate their disregard for international law, according to Lubinets. "They want to show that they are not going to be punished for it (by the international community)," he added.