He is perhaps the the biggest fictional rogue cop in history. If he were a real police officer, he wouldn't be a police officer very long. He would instead be in prison on charges of first-degree murder. Cops in real life only kill a suspect if there is no possibility of taking that suspect into custody alive and if that suspect were a danger to the general public.
Which killing would get him a murder charge? In the first film at least, every single shooting was a clear case of self-defense.
And "first-degree murder" no less. Takes one hell of a rogue cop to plan his suspect killings in advance.