Attempting to collect unpaid rents

[fgs]

We are attempting to collect unpaid rents from a person we had to have the courts evict from our property. The court rendered a judgment for the rents. We have asked an attorney to collect, but he says he would need either new address, social security number, and/or date of birth to proceed. Where could we find this type of info that is accessbile to the public? They aren't in the phone directory. Thanks