Call me Inspector Gadget

So I've been doing some detective work for the past 3 months now and finally managed to break the case. In Feb 2008 DH and I purchased a new living room set and wanted to donate our older sofa for a good cause. The sofa was in mint condition, considering I always took good care of it. So cutting to the chase, I made a huge sign and stuck it on the sofa stating, "Donation for Breast Cancer Awareness (scheduled truck pick up)" Well it was in my parking space and one of our neighbors thought it was cute to steal the sofa for themselves. I was vivid and I couldn't believe someone would ignore a sign that clearly meant "DO NOT TAKE!" Who in this world thinks they have more worth than going for a good cause. I just told my husband, "don't worry that the man upstairs is watching and they will pay for what they did." I already had plans that if I saw someone with our sofa moving in the future, I would seriously walk right up and slash the hell out of it. When they call the cops, I will show them the donation slip stating that item was missing and have pictures to prove it was ours. Yes, I am just that crazy. I'm a thoughtful person but ugly actions will pay in my book. Now 2 days a go, hubby and I went to speak with a neighbor 3 doors down that does carpentry work. As we are speaking to him, I notice our sofa right through their window. DH just tapped my leg for me to see it. Question now is, what to do? Hmmmm....Should I contact the association? Is it worth it and do I really feel they will do something about it? Probably not and now its too late. My father is a prankster and overall goofball. I told him what happend and he couldn't believe it. His advice is to go late at night and put crazy glue in their car door locks. =P He told me...well if you paid $600+ for that couch and they are taking advantage then let them pay to fix their car. The $$$ will not be returned in my pockets but the aggrevation is worth every dime. It will definitely make them think twice before messing with us. It's evil revenge but all I can do is say...Bwahahahaha!