Not that you are the morality police, but you don't want non-paying guests hogging the shower and laundry facilities.There is a LL on the Mr.

I got in touch with a contact at the police dept yesterday to look into the owners... 

I've actually had a police officer from a Township in Cincinnati, OH call me because my letter apparently scared one of their residents, lol.

Also, if he doesn't stop after numerous times being told to stop, am I able to call the police on him for having drugs or smoking in my home? 

I was going to ask my realtor to take me through to a few of them off Whetsel, then a couple of days later the horrible event of one of Cinci's police officers was shot and killed on those blocks of streets.  

I have done many evictions in Binghamton City Court .... usually holdover or nonpayments... difficult to get a tenant out who is objectionable only .... need a lot of proof, police reports, etc....

I went in with Loudoun County Police Officer and secured the place.

Or install security cameras and report them to the police.

The ROPs are tied into everything - police reports, school records, etc.  

You don't have to get keys back and you can just call the police if they squat or are trespassing...I see you are in Michigan...are you selling this with a land contract?