Inherited a Nuisance Property

[Cassidy Pathak]

I recently inherited what can only be termed as a nuisance property. As it has a newer furnace/ac, newer roof, and just needs a lot of cosmetic fixes I would like to renovate it. The problem is someone who used to stay their sometimes keep coming in and trashing the place I've spent 2k just on clean out and in retaliation the guy slashed the cleaning truck's tire. I've sealed every window/door on the lower level and installed surveillance so they can't enter. 

My question is how do you handle these people-particularly in STL? At some point I'm going to need to take the boards off and do the exterior/show the property. The cops attitude in the city seems to be 'if you're not actively dying go away' so they really didn't do anything. The neighborhood is coming back and it's hot for investment right now so I don't want to just give up.