How do you find out which mortgage company owns the note on a house?

[Melisa Gingrich]

I found a house that is trashed and vacant.  I've met with the owner of the house and he told me he is several months behind on his mortgage but has decided to let the bank have it back even though he admitted he's had no contact with them. I asked him to let me know who the mortgage company is so I can try to make a deal with them before it goes to foreclosure and he hasn't gotten back with me and is ignoring my phone calls and texts and it's been over a month. The county is telling me they don't know who the mortgage company is.