Police are not working hard enough here. 200 feet makes very little difference when someone is working a jackhammer at 2:00 am in the morning, or playing musics till the wee hours of the morning. Press them hard enough to either visit the site, or let you gain evidence.

Are there any easements in place regarding parking? Since they are renters exerting pressure on the landlord would be my next step. A letter from a lawyer can do a lot towards getting the process moving in the right direction.