I think I am not going to introduce myself to our new neighbors
Why don't you want to introduce yourself? It seems a bit cold not to.
They can't be trusted. I've seen them peeking from their window, why do you think they're doing that?
While I don't think you have to introduce yourself to the neighbors if you don't want to, it's the polite thing to do. Maybe they're peeking out of the window because they're nervous. If you introduce yourself, they may be more comfortable and act more "normal."
Not all criminals say they aren't criminals, you know.
You have a point, but if they are, wouldn't you want to know them so that you can keep an eye on them? But at the end of the day, it's your call and I'll support whatever decision you choose.