My grandfather grew up in NYC, in the early 20th century. He worked with cars when he was young, and knew cops. They used to have an elite underground organization called the "Suicide Squad". Basically, these were volunteers that would leave their badge at home, use their own transportation and weapons, and "take care" of people that they knew were guilty, but were somehow found innocent, or released, because of lack of evidence, connections, etc.

If any members of the police force that were "suicide squad" members were caught, they were sworn to secrecy about the squad and had to keep quiet, even if it meant serving time.

I'll tell you one thing: the cops did not treat child rapists and other assorted degenerates with kid gloves in those days.

My mother once told me a story about an attempted violation by a predator. While waiting for a bus, in the 1940s, she accepted a ride with a man, in upstate NY (where they had relocated from the Bronx), who offered to drop her off at her school. He didn't drive to the school, but headed out toward the highway. She told him that her father was a big Irish cop (which was not true) He didn't say a single word -he immediately turned the car around and dropped her off at school.