Steve:
Well number one, spot the shitmakers. Number two, make sure you've got the right culprits. Number three, prove it. Number four, force the jackets on them. Number five, make them do what you want, arbitrarily and without legal backing. Shades of Dixon of Dock Green feeling the villain's collar and the villain meekly saying, OK, it's a fair cop, guv. I've just spotted a cuckoo in the clouds. Next stop, bunches of vigilantes. Maybe a posse or two.

Alternately, assume that you can do F*** all about it, and allow it to continue.