Throw enough of them in jail - AND their supervisors - maybe things will change.
Then sue the bejeebers out of the city. Million dollar personal injury suits. And massive Civil Rights Violation Fines and Penalties. Punish the taxpayers who vote liberal scumwads into office who appoint and hire JBT's.
That's cleaning it up for them, and it's probably necessary. They'd be wise to start vigorously policing themselves. The "good" ones will find that process a lot less painful than any of the alternatives. I doubt they have the guts, individually or culturally, to do it.