What kind of threats did they bestow upon you? If it's anything physical, have a police report filed. If it was just, "we'll call the NAACP"
, yadda, yadda........have no fear.
Not sure of the laws in NC, but in some states, people have to occupy a space for more than 30 days before they are consider residents.
IF that is the case here, I would make it crystal clear to them that they are NOT qualified for tenancy AND that they are NOT residents of your house AND that they shall remove there belongings immediately. If they refuse, make it clear that you will place there belongings curbside for them to pick up.
Sorry to sound harsh, but your wife needs to learn lifes lessons the hard way.