If the police have any questions, they start at the original purchaser and track it forward. If you don't hear from them, probably no worries. If you do, tell them about the legal sale/trade. No worries on your part.
Looks like trouble in his future when he crosses the line and tazes the wrong person. Problem is, wife and children will pay the price when he gets fired and/or sued.
Just my 2cents.
Did you buy title insurance when you closed? If so , it may provide some legal assistance up to repurchase of your house in an unresolvable situation. I had the same thing happen to me back in 2000. I resolved the problem by purchasing the lot my septic lines were buried on, didn't have...