This has been driving me mad for years! I remember watching a TV series or one off (I THINK on the BBC) in the '80s.
A male teacher had told off a male student who then went all out for revenge. He convinced other students to kidnap the teacher with him.
I remember the teacher being tied up in a garage or barn somehwere and then they killed him - possibly accidentally. When the Police interrogated them afterwards the ringleader cleverly convinced the Police that the teacher had sexually abused him.
I think it was called "The Police" but I've never been able to find it anywhere or any reference of it. Does anyone else remember it?