I'd suggest she call the local police department and request additional surveillance. 

Video cameras and notepads are welcomed, as well as steel toe boots, gloves, goggles, and facemask....lol....really though.

Once you get wifi, I would recommend the Nest cameras.  

You could have a security camera but people just turn them off when they are doing something wrong.  

Sure, we know now how to execute on 1sts and 2nds (although we're still constantly learning), and how to complete surveillance on our servicers, attorneys, and other third parties etc. to @Patrick Desjardins' point.

Make sure to higher licensed plumbers to come in with cameras and inspect ALL the lines under the buildings during your due dilligence period. 

Would love to hear ideas on setting up security/cameras on property as we rehab these locations.

Looking for ideas on security and/or cameras as we go they the process of rehabbing our new home!!!!

My recommendations are: Cameras, if you can afford it.

Obviously on camera, caught and arrested.