[bko]

You don't need to buy securitized mortgages. You can buy the mortgages directly. They're called whole loans. Sourcing them might be a bit tricky and I think you have to be accredited investor. They're usually sold in blocks among banks and institutional investors. I doubt you'll be able to source one specific person's loans and when these loans are up for sale, they usually don't include personally identifiable information.

The market for non-performing mortgages is more ad-hoc and you can buy an individual mortgage. But finding who owns the loan of a particular person is difficult. Also you would have to go through the trouble of foreclosing on them.

[toast0]

It shouldn't be too hard to find who owns a mortgage. A mortgage must be recorded timely to be properly enforceable, so most are. Just have to know what to look for at the county records office (I assume you know where your nemesis lives)