You really shouldn't. Cops are never on your side.
I mean never is a strong word here. People are saved by cops every day. At least in my country. Just looking today news: women was arrested after being violent towards doctors in La Palma. Pretty sure doctors though cops were on their side.
You have to be sure to defend your citizen rights and prosecuted rights (if it even become to that). But that does not conflict to call the cops if you need to and if you are being victim of a crime they'll most likely help you. Once again, that's how it is where I live.