Unless you have a person go check if they did the work you can jnstall IP cameras to oversee the properties and check in.

Can't do that anymore due to cameras and phones. 

@Scott Trench Just about everyone has a video camera on their phone.

thanks for the Camera information, I will definitely look into this.

We also took other measures for security purposes - I ordered about six dummy video cameras that take a battery so a little red light constant blinks and No Trespassing Signs, Property Under Surveillance signs and installed them on and around the house on Day 1.  

The tenants were menaced and physical harm was threatened to the point where I am considering installing a camera and security system.  

theViewer.co is one that I'm checking out - it only takes 20 mins with the right VR camera to shoot and set up.

They evict everyone and add security gates and cameras and day care facilities etc... then they rehab and fill it back up with higher rental tenants and when they get to 85% capacity they finance it with a bank.

No one gets in or out of the street without being recorded by multiple cameras on private property.

Install cameras if there aren’t any there already.