When that PM contacted me, i learned that they knew that one of the tenants had a criminal record and still accepted these people.  

Sometimes I will run a full credit/criminal/history screening and sometimes I won't knowing that I already have a very qualified tenant on the hook should things go bad.

Then, they'd usually want a request via fax on letterhead, which I did not have, as a resident manager working for an old fashioned owner.Other than using other good sleuthing techniques and credit, criminal, eviction, employment checks - your next best defense is a month to month agreement.And remember that you can deny them for nearly anything you can think of.  

You also probably won't be able to verify their criminal record or do any kind of background search...

We verify pay stubs and previous landlord and do background checks/criminal checks.  

Applicants with criminals for relatives and friends aren't a protected class. 

@Mitchell Frisby just go forward with the eviction process and inform them that you will do everything within your power to collect on any damages to the property as well as press criminal charges for vandalism if they intentionally destroy your property (unlikely that will go anywhere unless you have solid proof they did it, and can get the police to do anything about it, but they don’t know that).

lol.With all of these applicants, criminal, credit and landlord references have come back clean/excellent.Applicant 1: First to apply, 3 room mates from out of state.

Many departments have a program where off-duty officers can be hired as security for events (they make sure the requesters are not criminals).Some landlords might be able to get this service for free.

Or at that point is it criminal trespassing and can have them removed?