These polices are designed to ensure prompt payment after a loss without the need to determine fault or whose property was damaged.

The Internet is not policed very well and the crooks know that.  

Checking police reports/filing a Freedom of Information Act request for the address should get you what you need, or at least further on your way.

Neighbors will not call police, if they see something.Not, yet, ripe for retailing.

Have her speak to the police and make sure they understand she is in a dangerous situation.

Pete police.

You could also have the tenants to bring you there police record by going to the nearest police station.

Not only would that show the tenant you are serious about getting to the bottom of this issue, but it could also help prevent (or help you in the event of having to call the police) further thefts.  

At the same time I feel like security cameras and smart locks you control with a smart phone would take care of most of those worries.You could even try using FaceTime with the applicant for an initial phone interview then ask them to text you a picture of their drivers license in case you or the police need to track them down later.

The old man is a retired police officer.