Negative.
Cops get caught committing crimes, arrested, indicted, found guilty, fired, sentence to prison time... all the time. It's a constant fact of life, and in a lot of cases, police officers do face harsher penalties and get less breaks because the system tries to set an example of them.
How do I know this?
Because I'm a cop and I work in the criminal justice system (in some county in some state I won't mention)...
What do you know?
I'll tell you what you know... only what the media tells you. The media is not going to report on every cop who is being indicted or facing charges or canned from his/her job. Why? Because it's not interesting enough news to boost ratings, and the media (national, not local) won't report it.
But trust me, cops get caught and charged. You just don't hear about it.
Do crooked cops sometimes get away with things? Of course.
But do criminals sometimes get away with things too?
YES. YES.
and
YES.