Rep. Duncan Hunter (R-Calif.) made a pretty extraordinary claim on Fox News this week, telling a national television audience on Tuesday night that 10 Islamic State militants were caught entering the United States through the Mexican border. The far-right congressman was categorical: Hunter said in no uncertain terms that this has already happened, but “there’s nobody talking about it.”

The California Republican added that he knows this is true “because I’ve asked the Border Patrol.”

Right-wing media outlets were predictably excited by the baseless claims – National Review, citing Hunter’s comments, asked , “Could the administration really successfully cover up something as big as this?” – but there’s a small problem. Neither Hunter nor his allies have any verifiable evidence to bolster the allegations. I mean that quite literally – there’s nothing from Border Patrol, nothing from other members of Congress or relevant committees, nothing from the Mexican government, and nothing from the Department of Homeland Security.

On the contrary, DHS described the claim as “ categorically false ” and Secretary Jeh Johnson suggested Hunter has no idea what he’s talking about.

And that leaves the far-right congressman with a choice: Hunter can scale back his explosive claims or he can stick to his guns. Take a wild guess which course the Republican prefers

Hunter spokesman Joe Kasper said the congressman stands by his comments. “A high level source informed the congressman – it was also said that DHS is actively discouraging any talk of IS on the border,” Kasper said. “The congressman was conveying what he knows – and what he was told,” he said.

Hmm. Hunter has no proof, but he has a source he won’t identify, who gave him information that literally no one else can verify, about an important claim unsupported by facts.

Wait, it gets even better.

Kasper emailed me yesterday, encouraging me to check out a blog post from a right-wing legal group called Judicial Watch, which also claims to have secret information about ISIS terrorists arrested in Texas. There’s no independent evidence to support this, either, though Hunter’s office apparently takes it quite seriously.

In a follow-up email to The Rachel Maddow Show, the congressman’s aide added that the 10 ISIS terrorists Hunter referenced on the air should probably be referred to as “foreign nationals” with “associations” to the terrorist group. The congressman’s office did not feel the need to share this information with federal law enforcement, the aide added, because Hunter’s source is already in law enforcement and there’s “no need to inform the person that is informing us.”

While this continues to play out, I’ll be curious to learn how Duncan Hunter made the decision to share this incredibly important information with the American public. Under normal circumstances, if a member of Congress obtained secret information that literally no one else has about terrorists entering the United States, one would assume the lawmaker would hold a press conference, issue some kind of press statement, and/or announce an upcoming congressional hearing on the revelations.