I have purchased an Arlo camera so that I can find out for sure who it is but I'm not sure what I can do legally once I find out if it is the occupant I think it is.

I'm going to digital entry (four students, they lose keys a LOT) and smart home features (like turning off the HVAC when doors and windows are open because students are apparently idiots and do, in fact, air condition the whole darn neighborhood), plus a few exterior cameras. 

. - i.e. digital door locks, wifi controlled thermostats, ring camera on the exterior entrance.  

I used to have international nannies, and they did not know the basics of how things work in the US. 

Well you can police the stuff that will happen, put up cameras, drive there more, become brilliant at property management, but you will see them litter the place more, leave busted up cars there more, stuff on the curb (fines), make more noise, be more destructive.   

Underestimated how dirty something that looks clean on camera can be. 

@Marshall Henry set up a camera now!

If not, might put a camera on that meter (and maybe others) to see what is going on. 

Cameras change the game, pure and simple, especially cameras with digital recording, night vision, web upload capabilities, motion detection spotlights.

It may take some time, and she may signal to the cameras and have a bouncer throw you out, but if you keep at it, you'll find one who will go for it.