Vadim Shishimarin admitted shooting a 62-year-old man a few days after the invasion began. He faces life in jail.
The prisoner was brought into the tiny Kyiv courtroom in handcuffs, flanked by heavily armed guards. He looked nervous, and kept his head bowed.
The widow of the man killed was sitting just a couple of metres from him.
She wiped tears from her eyes as the soldier entered court, then sat with hands clasped as the prosecutor set out his case, describing the moment Kateryna's husband, Oleksandr Shelipov, was shot in the head.