Ukraine hunts for Russia collaborators in liberated regions

One city recently liberated by Ukrainian forces is Kupiansk, in the east. When Russian troops took control of it early in the war, many civilians left. But now there are questions over those who stayed put, and whether they collaborated with the Russians.
DW's Mathias Bölinger visited Kupiansk, where he found large parts of the city destroyed, and many residents struggling with questions of trust and guilt.