[b112]

Social security numbers are not unique. In the old days, mistakes would happen, and some people would get the same one.

This person could have been an illegal, but there is a non-zero chance you just both had the same one. It does happen, or at least did.

[eszed]

That's a fair point, but in the interests of a concise story I left out a couple of details: there were three different names associated with my SSN; all of the jobs were agricultural; there weren't any bank account, housing, or other identity-markers associated with my number. (I don't know how much of that I would have been able to figure out on my own, or even if my buddy should have told me that much, but it's nice to have friends in useful places.) I'm pretty sure about what happened.

Sidenote: I don't bear any ill will towards whoever used my SSN. It's not like I was targeted, or even that any harm to me was intended. This was a "hack" of a dysfunctional immigration and employment system, in a way that's totally obvious and easy to anticipate. My ire is reserved for those in positions of responsibility who maintain a regime that is manifestly not fit for purpose.