How to deal with kids trespassing on my neigbor's property

[Kolbey Pruitt]

I have a situation where a couple of kids (15-16yrs old) walk through the back yard of my neighbor next door. This has went on for more than a year and it didn't bother me a whole lot. A little over a month ago however, I heard a loud BANG from just behind my backyard (there is a small greenbelt there between my neighborhood and the next). I quickly looked out the window to see the two kids had fired a handgun about 50ft away from my property. They then proceeded with their usual routine through the neighbors yard. It was at this point that I decided something had to be done so I looked up the owner of the duplex next door and explained the issue. I suggested if they repaired their fence in the backyard and put up a privacy fence on the side (like all of the other duplexes on the street) it should deter them from coming through anymore. Well they did as I asked which was great! Today, however I saw the two kids climb over both 6ft fences. Any recommendations would be much appreciated.