All of these extra costs associated with overtime etc because of these riots and looting are a direct result of employing shitty cops and completely avoidable. The costs should be taken directly from the pension funds of cops as far as I’m concerned, cities should not bear the costs of overtime because of riots caused by cops killing people.
If we had a critical mass of good cops, we likely would need less overtime overall because the relationship would be better between law enforcement and citizens, especially minorities.
Alternatively, you could require insurance, similar to medical malpractice insurance, that pays out for law enforcement malfeasance. If you’re uninsurable due to your actions (egregious and/or chronic), you’re no longer a cop. The cost to your colleagues (premiums) also goes up because of your behavior.
This takes the financial burden off taxpayers, but still uses economic incentives to encourage the behavior we expect from public servants.
It puts a strong incentive on those to take responsibility for their coworkers. To cultivate a culture of integrity, through interactions, through hiring and firing, through setting an example for those you lead. Cops love to talk about having each other's backs; let's see them put those words into action where it counts.