Welcome to the 21st century where thieves don't bother breaking into homes but rather steal the house itself. The FBI is seeing cases of criminals combining identity theft and mortgage fraud to steal a homeowner's biggest asset. Here's how it works. Thieves identify a home (vacant or occupied) and the owner. Then, they steal the owner's identity and secure the deed to the home, sell the home to an unsuspecting buyer, pocket the profits and disappear. The homeowner continues paying the mortgage the entire time.
The scariest thing about this scam is it's hard to detect and prevent. Homeowners are encouraged to be suspicious if they receive information from a mortgage company that is not their own. Instead of throwing this information away, open it up and figure out why they are contacting you. Homeowners should also check in their county deeds office from time to time for any paperwork or signatures they do not recognize. Contact your local FBI office if you suspect you are being victimized. These scams are rare, but the FBI is watching to make sure they stay that way.
I think I saw this on an episode of "Law and Order" but they did it by convincing the homeowners to sign the deed over to them to prevent foreclosure. They then resold the home with the old owners still in it.