"I fired at him, he fell. We went further, Russian serviceman Vadim Shishimarin told the Security Service of Ukraine.
He is accused of killing a civilian in the Sumy region. Shishimarin faces up to 10-15 years in prison.
He pleaded guilty at a court hearing on May 18.
The Russian serviceman was charged with "Violation of the laws or customs of war."
According to the investigation, on February 28, a 21-year-old occupier killed an unarmed pensioner in the Chupakhivka town, Sumy region. He was riding a bicycle along the side of the road. After the shelling the man died near his home.
The accuser has material evidence - the phone of the victim and 5 automatic machines of the Russian military servicemen
The first hearing in the Shishimarin case was on May 13
The photo:Victoria Ivleva
Yaroslav Semchenko