They also have a lot of political pressure to "solve crimes," which is literally a score board. I'm not excusing what they do in any way. It's a big mess of a system with too many incompetent bureaucratic careerists who seem to be short on ethics.
I liken it as a game which didn't take hackers into account when designing the system, and the hackers are now rampant, ruining the game, except it isn't a game.