Depending on your city/area you may have such data available from the local police department or the sheriff's department.

We had the police out today to file a report and press charges, only to find out that we can't file charges because we signed a contract.

You asked about how to deal with squatters...I assume you have a property in which you've got some unwelcome people hanging around. 1) Post No Trespassing sign on your property2) Make sure all windows and doors are secure3) If you catch them in the property, call the police right away.

No tolerance the police will be called.

Property taxes are a source for any municipality to use as its tax base, sources from while to fund all municipal expenses like street clean up, street lighting, traffic lighting, police and fire fighting service etc. etc. 

Let the police handle it.

If the problem is really bad you have the police and fire dept nearby.

@Jd Martin, ah, it looks like the vote police have waived their objections...

If you find one it will need significant repairs or be in the worst part of town, have bad tenants and the police won't even go out to it. 

You can't pay for police and fire when 40% of reduced finances go to pay debt each year.I am optimistic that Detroit will do better coming out of bankruptcy.