How can I legally warn potential homebuyers of seller's faulty business practices?

Two years ago, I purchased my first home. The house was sold through a real estate company;however, the individual owner remodeled the home as a "flip-house" and never actually lived here. He hired incompetent people to rework the entire home. This individual has now purchased my neighbors home. I know the house will require several repairs and updating. My question is how do I warn potential home buyers of this man's con artist ways. I do not believe I can do anything about the money pit he sold me, but I would like to save someone else some of the catastrophes that i have endured. Can I put a sign on my property warning people to avoid buying one of his homes. I want everyone to know the sorry work this man does. Please help.