Perhaps the best response would be to find out who the responsible officer is, then publicly shame him. Policemen know that they can do an awful lot before their own department will turn on them, but the same cannot be said of the public.
This should in no way constitute any threat to the life of the officer or his family, just that he should be ostracized by the public knowing who he is, and refusing to voluntarily have anything to do with him.
If he confronts someone on the street for any reason, that person should request a police supervisor be present; in many situations police are *required* to summon a supervisor is the public requests it. And when the supervisor shows up and asks why, the person can say that they “have no confidence” in the officer.
Police supervisors tend to get annoyed when they are told this, and not at the citizen. If it happens two or three times, they figure that the officer is more of a hassle than he is worth.
“Puppy Killer” signs appearing a oh-dark-thirty in his front yard ...