Long story short: I want him out of there ASAP.I've had relatively little luck with the police.

Go to city hall, go to the police department.

Got told by nebors, tenants (tenant) were arrested for drug possession.( I am beyond speechless)   I called police department to find out more information on it, the only thing they were able to give me is the wife was arrested for sure. along with few other ones in the house.

I was informed by a neighbor that as recently as a couple years ago, the one house was basically a brothel, it's been cleaned up once the neighbors got the police involved but I imagine the tenants aren't the best.   

I'm retiring from being a police officer, so perhaps I can follow in David's footsteps. 

Or make friends with a police officer and have them accompany you. 

Long story short the police were called and she was asked to leave.

I’m unable to reach the tenant via phone or email and I want to access the property to get a certificate of occupancy and to document the condition of the property.Can I just go there with the police and if no one answers the door bust it open?

At this point we've been reduced to just calling police for noise complaints when other tenants let us know but I'm not sure if there is anything else I can do shy of aggressively demanding the other owner get his tenants under control.

Most of my properties are in smaller communities and I have waiting lists for tenants who are typically Police and Teachers in the community.