Sergeyev graduated from the Kazan Tank School during the Soviet era. In 2020, he participated in protests near the Atlant plant, after which he and his wife left for Poland. He played in an amateur hockey league.
He allegedly returned to Belarus due to serious health issues. According to acquaintances, Andrei developed lung problems and underwent surgery in Belarus.
It is known that Andrei Sergeyev was detained in August 2025, when he was already leaving Belarus for Poland (according to a source, he was working as a long-haul truck driver in that country). He was detained at the border crossing in Brest. A criminal case was opened against him, and Sergeyev was sent to the Kolyadichi pretrial detention center.
Around February 2026, the investigation was completed and the case was sent to court. According to the source, Sergeev was charged with " participation in military operations on the territory of a foreign state " and was also somehow linked to the "Gayun case."
