My father (then a local public person) had a driver who used to take us to school in his absence. Nicest guy ever, would joke around, take us to other places when we didn't wanna go to class, absolutely the best. One day I was looking for the fire extinguisher in the car (then required in my country) and found a Glock G19 underneath the driver's seat.

I asked "what the hell?" and he said "this is for me to use in case somebody talks shit about your father".

Upon some investigation, it turns out that the nicest guy in the world was actually living in my city because he was on the run for a murder he committed in another city many years back. The nicest guy in the world had an altercation with another patron at a bar, while drunk, broke a beer bootle on a table, stuck into the stomach of the other guy, and twisted left and right until internal organs started showing.

I did befriend a murderer once.