There is an entire industry of legal professionals dedicated to this line of work who have databases they use specifically for tracking people down.

Not a lot for a contribution, but he has sizeable IRAs to roll over too that will enable him to buy several more rentals with 40% down and earn in the neigborhood of 16-20% a year. 

As PART of a tenant screening process, you could check the dates and addresses on the application against an online database that simply shows the 3-5 question summary reference for that property during that time frame.

This will enable you to list properties legally for others.

In my state there is quite a bit of prep and sign off you need to screen tenants, especially if you want to pass through the screening cost.Also I would go manually search for unlawful detainer / eviction proceedings on their name on your local case databases.

I can work my way around a spreadsheet and databases but the most helpful my degree has been to me was landing me in real estate companies that ended up catching my interest in REI.

I have a database built up over 14 years with thousands of companies nationally for retail property management companies, retail brokerages, retail developers, individual ultra high net worth owners, REIT's, and partnerships.    

Furthermore, I looked on the NH Deeds database for this property and this database looked like something I worked on in Engineering school back in the 80s...the whole thing just made me too nervous that I would be overlooking something. 

The Borax basically kills them as soon as they hatch and continues to do so enabling it to break their life cycle.

This enables me to determine if I want to renew with them.