Surveillance

Most of public areas, especially in cities, are under constant surveillance. Police cameras are running face recognition programs in real time. Allegedly, surveillance AI identifies and flags on the police radar only people with criminal record, but who's to say that all the rest of us can't be ID'd? Technically it is certainly possible, and it makes sense from biometric data accumulation perspective.
Police shares the surveillance feeds and recognition databases with freelance subcons. Freelancer's camera or implant becomes a part of the surveillance - eg the places and suspects that he or she sees are transmitted into the AI. Police might restrict the ranges of suspects that show up as targets for subcons.
And yes, it means that theoretically cops can track every perp to each hiding place and arrest all of them. This is not happening. Firstly, there's just too much crime, minor to major, to really act on every piece of surveillance. Secondly, coppers don't do for free what they could do for cash. Their brain sponges sort of combine these two factors into the case prioritization model (in the time not occupied with spending bribes and abusing suspects). The most public, politically important, or super violent cases will still receive the full support of surveillance tech and the detectives' attention.