Busted: Fox host Chris Wallace fact checks Sarah Sanders on air

It's an unusual day in the Fox news sphere when one of their own busts Press Secretary Sarah Sanders for her alternative facts.

Fox host Chris Wallace interviewed Sanders on Sunday, and when she claimed (at 9:46) that "nearly 4,000 known or suspected terrorists come into our country illegally, and we know that our most vulnerable point of entry is at our southern border..." Wallace abruptly cuts her off to set the facts straight.

"I know the statistic, I didn't know if you were gonna use it but I studied up on this. Do you know where those 4,000 people come from, where they're captured? Airports. The State Department says there hasn't been any terrorist that they've found coming across the southern border," he says.

Although cornered, she soldiers on, but Wallace doesn't let up. The child-caught-in-a-lie look on her face is priceless.