How to Screen Background of People without Soc Security Numbers?

[Patrick M.]

Greetings all- I'm renting properties in an area where there is an increasing number of highly educated immigrants seeking rentals near our major universities. I was approached last week by a nice young couple from Latin America who are getting advanced degrees. They give off all the right "good tenant" vibes but I realize I don't know how to do a background check on people who don't have a US social security number.

Any tips?