I was a probation officer for 7 years and my experience with cops is, find the right one they will happily go talk to the guy just because they like the confrontation. Find out who the "super cop" is in your neighborhood. Since you live in a cul-de-sac, you have neighbors. I would suggest you ALL get together and go down and talk to the guy. And, although I usually follow the law, when it comes to my child, if there was any threat they would be hurt, something would mysteriuosly be happening to that guys bike.