Earlier quoted context omitted.
How could they know who did it? It could be any one of their neighbors, and most lots have 5 adjacent lots. In a place I used to live, there was a rooster that would constantly crow. Someone killed it. I wasn't involved but I'm certainly glad it happened. That rooster was driving the neighborhood insane. The police were useless in that situation. They never cared about noise complaints. Basically if the state doesn't…
That's why police exist in the first place (if you're not thinking too cynically about it). The main job of police is to reduce vigilante justice and mob violence. If the police don't shut up someone's dog, convict a blatant rapist, or punish a murderer, expect the people to take it into their own hands.
The police shouldn't be, and aren't, tasked with, those things.