If broken in already, then best to board up window, but still can easily be broken into.Not sure about the local police in Memphis, but Las Vegas PD is aware of squatters and have squads assigned to this specifically.

I also called police department to report harassment and threats.

I suggest that before you buy a property in a 'ghetto' area that you get to know your market very, very well: spend a whole bunch of quality time with local police report website if it is available in your area, drive throught the neighborhoods you are considering at different times of the day (and night).

Nother guy would wear a shirt said police on back so no one would mess with him.  

When they can get the police to show up within 30 min, when they can clean up the thousands of houses the land bank lets sit blighted, when they can assess properties for taxes correctly, when they can fix the water dept so they don't have to gouge properties in Detroit - I'll comply. 

Also one thing to consider is police response times.   

I was clueless, of course,  until the police called me.  

Maybe the police will find something else to do instead of traffic tickets.

Request police responses over a 12 month period. 

You should include rules about, noise, parties, lost keys, local violations about that cause fines, these can include garbage, police calls, sidewalk snow removal if tenants are responsible.