Ukraine's prosecution chief stated on Wednesday that a 21-year-old Russian soldier will testify in the country's first war crimes trial over Moscow's continuing assault.

As per a statement from the prosecutor's office, Vadim Shishimarin is suspected of shooting an unarmed 62-year-old civilian from a car window to prevent him from testifying to an attempted robbery.

Shishimarin accompanied four other fled servicemen and stole a car from outside the town of Chupakhivka after his convoy was attacked in northern Ukraine on February 28, according to the statement.

The unnamed individual was riding his bicycle on the roadside near his home when the reported crime occurred, the office reported.

According to a statement from Prosecutor Iryna Venediktova's office, one of the service members instructed the convicted to kill a civilian so that he would not denounce them.

"The man died at the scene barely a few hundred meters from his home," the report continued.

On counts of war crimes and premeditated murder, the Russian army man in custody might face life in jail.

The prosecutor's office issued a blurred photo of Shishimarin but did not say how he ended up in Ukrainian captivity or what became to the other members of his group at the time of the suspected murder.

The case was filed in a criminal court this week, setting the stage for a trial to begin.

"SBU [Ukrainian secret services] lawyers and inspectors have gathered adequate evidence of his participation in violations of the laws and customs of war mixed with planned murder," a  spokesperson revealed.

The accused, the spokesperson said, risks 10 to 15 years imprisonment or life in jail for these offenses.

Since the February 24 assault, Kyiv and Washington have charged Russian troops with committing atrocities, prompting a major evacuation of over six million civilians, many of whom have witnessed and reported crimes such as torture, sexual abuse, and indiscriminate damage.

War crimes investigators from the United Kingdom and the Netherlands have arrived in Ukraine to assist local and International Criminal Court teams investigating alleged mass atrocities, notably in the Kyiv neighborhood of Bucha, where at least 20 dead were discovered on April 2.

Many of the reported crimes were exposed last month after Moscow's military servicemen abandoned their attempt to conquer Kyiv and withdrew from the area around the city, uncovering mass graves and remains scattered across streets and yards in villages like Bucha.