Hmm, good point. My X-Files knowledge is no longer encyclopedic but this one seemed to go past simple borrowing, though I imagine X-Files didn’t invent the concept. Wasn’t there an X-Files were a father was protecting and concealing his mutant baby that was feeding on innocent bystanders?
It wasn’t the sheriff’s wife and son. The guy that owns the land that the field was on was some kind of mad scientist at one time, it was his wife and son. The agents found lab equipment in the farm house and Olive heard sounds with her new super hearing. They found a bible with a news article in it that lead them to the theory that the farmer killed his family. So they dug the bodies up.
The sheriff just ended up being ate later. Since you have internet you can view the whole episode on hulu.com, if you are in the US.