Citizen Kochetov in a crowded bus

Citizen Kochetov, being in a crowded bus, accidentally noticed that the 12-year-old Hvorostov made an incision with some sharp object on the leather bag of Kochetov’s wife and was trying to get his wallet out of there. Kochetov grabbed Hvorostov by the hand, and when he tried to escape, hit him with an elbow in the stomach. At the nearest stop, Kochetov pulled Hvorostov from the bus by the scruff of the neck and, despite the latter´s requests not to beat him, he inflicted several blows on his teenager with his fists and legs, causing him moderate health.
Give a criminal law characterization of Kochetov’s actions.