In the first war crimes trial stemming from Russia’s Feb. 24 invasion, a Ukrainian court sentenced a Russian soldier to life in jail on Monday for murdering an unarmed civilian.

Vadim Shishimarin, a 21-year-old tank commander, pleaded guilty to killing 62-year-old Oleksandr Shelipov on Feb. 28 in the northeastern Ukrainian town of Chupakhivka after being commanded to do so.

Shishimarin, according to Judge Serhiy Agafonov, fired six rounds at the victim’s head from an automatic weapon while carrying out a “criminal command” from a higher-ranking soldier.

Shishimarin, dressed in a blue and grey hooded sweatshirt, sat calmly in the courtroom from a reinforced glass box, showing no expression as the decision was read out.

The trial is very important for Ukraine, which has accused Russia of atrocities and cruelty against people during the invasion and claims to have discovered over 10,000 suspected war crimes.

Russia has denied any involvement in war crimes or targeting of people.