Don't commit crimes and you won't have to worry about the cops.
More like don't commit crimes and don't have the audacity to report crimes committed to you. I was first raped when I was 14. A couple months later I broke down and told a teacher, who told our school's assigned officer, who bullied me into reporting. Seriously. The whole "If you don't grow up and do your duty to report this, he will hurt someone else and that will be on your hands" bit. So he took me to file a complaint in the county where the incident occurred, where they sat me down (at a point where I couldn't even physically talk about what had happened without completely shutting down- I was NOT ready to do anything remotely like this) with two male officers. The officers then proceeded not to listen to much of anything I said, and not to try to get answers for the things it was obvious I couldn't say (because I would make half a sentence and break down in tears). By the end they were humiliating me and saying I had wasted their time, because I had gone out with my assailant that night, and I had kissed him willingly. You know, before that whole he then proceeded to threaten me with a knife and rape me thing. Obviously the only solution was still 'buyer's remorse': the term used to my face. All of this, also, without indicating to the parents of a minor that it was occurring, so I was completely on my own.
Before this I had volunteered for several years with the police in the town where my school was located, teaching elementary children basic safety (know your parent's number, your address, basic traffic laws so you can walk safely from A to B). The man who raped me was an EMT. It was a small town and once they found out who I had identified I received a lot of cold shoulders from the officers.
All of this led fairly directly to me not reporting my subsequent long term abuse. And when my friend date raped me two years ago my immediate thought when considering whether there was anything I could do was that I didn't want to be explaining to two male officers under the assumption I was out for some sort of revenge why I was accusing my best friend, someone I spent time with alone often, of raping me. Particularly when I went to his home willingly, alone, at night.
I have met some officers who have been wonderful and compassionate. But these are not the people I have had to deal with in an official manner.