Hire a team of surly neighborhood kids, maybe 5$ per day 3 days per week. Their job will be to bash on the people's door at all hours of the night, run away, and repeat 5 times at 1 hour intervals.
This way it cannot be fully linked to you, but interrupts their home comfort like they do to you.
After about a month, act like "The Godfather" and tell the guy; "I can make this alllll go away...For a price" etc...Then he will be at the end of his wits and willing to do anything.