The first war crimes trial since Moscow's invasion of Ukraine, against a Russian soldier accused of killing an unarmed civilian, gets underway in Kyiv on Wednesday.
The trial, expected to be followed by several others, will test the Ukrainian justice system at a time when international institutions are also conducting their own investigations into abuses committed by Russian forces.
Vadim Shishimarin, 21, will appear at Kyiv's Solomyansky district court from 2:00 pm (1100 GMT) over the death of a 62-year-old man in northeastern Ukraine on February 28.
Charged with war crimes and premeditated murder, the soldier from Irkutsk in Siberia faces a possible life sentence.
"He understands what he is being accused of," his lawyer Viktor Ovsiannikov told AFP, without revealing the case for the defence.
Ukrainian authorities say he is cooperating with investigators and admitting the facts of the incident which came just four days after the Russian invasion began.
Prosecutors said Shishimarin was commanding a unit in a tank division when his convoy came under attack.
He and four other soldiers stole a car, and as they were travelling near the village of Shupakhivka in the Sumy region, they encountered a 62-year-old man on a bicycle.
"One of the soldiers ordered the accused to kill the civilian so that he would not denounce them," the prosecutor's office said.
Shishimarin then fired a Kalashnikov assault rifle from the window of the vehicle and "the man died instantly, a few dozen metres from his home", they added in a statement.
In early May, Ukrainian authorities announced his arrest without giving details, while publishing a video in which Shishimarin said he had come to fight in Ukraine to "support his mother financially."
He explained his actions saying: "I was ordered to shoot, I shot him once. He fell and we continued our journey."
The case is proving challenging, according to his lawyer.
"This is the first such case in Ukraine with such an indictment. There is no relevant legal practice or verdicts on such cases. We will sort it out," he said.
Ovsiannikov said he had not seen any rights violations by the authorities.
Ukraine's chief prosecutor Iryna Venediktova underlined the importance of the case for her country in a series of tweets.
"We have over 11,000 ongoing cases of war crimes and already 40 suspects," she said.
"By this first trial, we are sending a clear signal that every perpetrator, every person who ordered or assisted in the commission of crimes in Ukraine shall not avoid responsibility."
Two Russian servicemen are due to go on trial from Thursday for firing rockets at civilian infrastructure in the northeastern Kharkiv region.