- While the (especially Anglo-American) courtroom is adversarial, prosecutors shouldn't be at all compensated (money, promotion, etc.) by who they lock up. Something based on future crime rates would be much better.
- Rather than DA's needing the police, the police should need the DA. Arresting someone that isn't convicted should reflect very poorly on the police.
That side, both groups are badly in need of complete replacement, which makes it hard to talk how they ought to work together when the real "ought" goes so much further
In fact, the most effective way for prosecutors to improve their crime rate would be to persecute the high-crime racial demographics until they move out of town.
[1] edit: the non-organized-crime kind
It's not great to rely on intermediate performance, but it is often less worse than the alternative.
What? A prosecutor’s purpose is not to prevent other crime nor to reduce recidivism. It’s strictly to ensure that crimes that do happen meet justice.
“Unsolved crimes” might be closer, but the prosecutors would definitely need to absorb the detective arm of the police branch at that point.