The first trial of a Russian soldier for war crimes in Ukraine since the invasion concluded Monday with Sgt. Vadim Shishimarin, a 21-year-old from Siberia, sentenced to life in prison for  premeditated murder and violating international laws for war. 

Shishimarin, a captured Russian tank-unit sergeant, fatally shot Oleksandr Shelipov, a 62-year-old civilian man in the head in late February. Shishimarin's defense had argued he was carrying out what he perceived to be a direct order that he initially disobeyed. He had pleaded guilty and asked Shelipov's widow for forgiveness.

During the trial the three-judge panel heard that Shishimarin was ordered to kill the man so he wouldn’t be able to report them to Ukrainian military authorities. Shishimarin fired his Kalashnikov rifle at the victim through the open window of a car.

"I was nervous about what was going on. I didn't want to kill," Shishimarin said at the hearing in Ukraine's capital Kyiv.

Ukrainian Prosecutor General Iryna Venediktova previously said her office was readying war crimes cases against 41 Russian soldiers for offenses that included bombing civilian infrastructure, killing civilians, rape and looting. Venediktova's office has collected more than 10,700 allegations of war crimes against Russia involving more than 600 suspects, including Russian soldiers and government officials.