Nine oranges

There's a serial killer in the area. Operatives immediately dubbed him "the sculptor": after the massacre of the victim, the killer dug the victim up to his chest in the ground and smeared the upper half with cement, resulting in something like a bust. For a long time no connection could be found between the first victims, but in the end it turned out that all the victims were in the same class. School resentment of one of the students twenty years later fell on the heads of the boys of the unfortunate class. But who is the aggrieved one? Or offended? What is he taking revenge for? Suspicions shift from one person to another, but mistakes become clear very quickly... the number of victims increases, and the circle of suspects naturally