Without dates, it's hard to know how far apart the incidents were but if the one where the plumber came out and the one where the boiler gave up, I would call that plumber and ask him about it.

TerryAll good advice.Clearly if a gun or knife is involved in an incident it is more dangerous.

Send a "Demand" letter outlining the incident and the amount of damages to the Broker by Certified mail.

Then she needs to get help and not on his dime....yea this is definitely not the first incident 

Craig, you want to charge a fee just to weed out these potential incidents, as the future tenants have no skin in the game, therefore they will be much more likely to flake out at any given moment and you have extended yourself and your time.

I'm thinking I'll call the police department and see if any neighbors reported the incident, or if any other houses were shot.

I would put something in writing (if you haven't already) about incident reports.

All it takes is one little incident and you're wishing you hadn't been the nice guy and said yes.

There was one incident where a stolen car entered the neighborhood, and the thief was found sleeping in the car.

I am selling my condo in a small four-unit building to start my real estate investing journey and wonder if the incident may make my condo harder to sell.