I truly feel for you, I'm sure you didn't "purposly" trap your neighbors cat, rather one that was using your yard as a litter box. Unfortunately, as long as cat owners allow their cats to go outside, there is a chance that bad things will happen to them. I'm a volunteer with a rescue group and a foster mom and I can't tell you the number of times I have taken in a kitty that has obviously had a loving home. Thankfully we are a no-kill shelter so all the ones I have fostered are now in their forever homes, but none ever found their way back to their original home. Like some of the others who have responded, I would contact your local police department and make a report of harassment. Best of luck.