Got a call at 8:00pm, caller ID listed as "Texas Call".  Cross referencing does bring it up as a Houston, TX, cell phone.  Caller asked for homeowners by name, stated correct address, said it was a "federal matter".  When I started grilling him with questions, he stammered for answers.  He got very flustered when I told him to send a federal agent to the house to discuss this federal matter with the homeowners.  He is clearly not a federal agent.  I'm not sure what his end game is, but it cannot be anything good.  I hope this helps someone avoid any trouble from this caller.