I kept saying that I was going to quit watching it because they were murderers and corrupt, but I finally did give it up after the grenade murder.
I only saw it in re runs so I saw it in a pretty short time.
That was the whole premise of the series - "Does the end justify the means"?
The last episode leaves 2 of the detectives dead, one being arrested, and the main character Mackey left working a desk job with no friends, nobody who will trust him, and the one thing he did care about (his children) gone. So it did show that there is a price to pay.