Because of this, it has a failing police and fire department, TONS of vacant properties so no tax revenue.

When do you need to think about umbrella polices? 

I can tell you it is impossible to police the number of occupants even if it was worth my time.  

Around here the self appointed sign police (bandit signs are illegal in most municipalities here) will damage or remove them.Could be competition and it could be people not wanting your advertising in their town.

They are selling the note to Wall-Street within 30 days and they aren't policing the houses.

At the very least, talk to the police before entering the property.

I've heard of people calling the police department and asking for statistics about the area before moving there.  

ONE THING IM NOT SURE IF THE POLICE AN TRACK THAT OR NOT.

Should we call police to get in with his permission and replace the lock?

I was a police officer here for 18 years, doing investing on the side to supplement my future pension, but recently things have really started taking off and it overtook my full time job, both in time and pay, so I resigned and am now doing full time investing.My main strategies have been holding rentals, and more recently flips (with very extensive rehabs).