It was a private investigator hired by Orly Taitz who discovered that information about SSN 999-xx-xxxx.
Unfortunately I can’t remember his name right now; when it comes back to me I’ll let you know.
In the meantime, if you can’t wait, the information is posted in a number of threads here on FR. Search for SSN.
The PI’s name is Neil Sankey. He used to be a Scotland Yard detective.