Tenants Bf has apparently moved in unannounced

[Tony Cavalli]

I was made aware that my tenant's Bf or baby daddy has apparently moved into the house with out notifying the property manager or myself... How should I handle this situation? Rent still comes in on time, but my manager has stated that when work is being on the property that this gentleman is always there by himself playing video games or something. On top of that a nice older (hotrod i guess) car has been there as well. I believe that its his...  Do I step in and make him fill out an application and run his credit? or leave the issue alone since rent is coming in on time? 

@Ramon Jenkins