Do you arrest a man beating his wife? What do you think happens next? That is not your job. You are supposed to arrest the bad guy. Well, it used to be that way.
You are another one missing the point here. How about you are a cop and you arrest another cop who is a meth-addicted psycho, who has the full backing of the department? How about that one? I'm sure you have it all figured out, because you've been there, done that, right? And remember, NO ONE will touch him, but you've got the answer.
I'm old school, which means I know BS when I see it.