The Finnish national prosecutor's office did not name the person, but according to Finnish media, it is a 37-year-old Russian man who has lived in Finland.
"The charges concern the suspect's activities in a unit called Rusich, which has fought alongside the Russian-backed separatist region of Luhansk against Ukraine," the Finnish prosecutors state.
The man, who was the deputy commander of the unit, is accused of killing 22 Ukrainian soldiers and seriously injuring four, along with his soldiers. He is accused of actions that "violate the laws of war regarding warfare and the treatment of wounded and killed enemy soldiers". The man himself denies any wrongdoing.
The 37-year-old was arrested in July 2023 at Helsinki Airport when he was on his way to Nice in southern France with his family. According to information in Finnish media, he had - despite an EU-wide entry ban - managed to enter Finland, among other things, with the help of a new identity.
Finland's Supreme Court has previously ruled that he cannot be extradited to Ukraine, due to the risk of him being subjected to treatment that violates his human rights there.
