One of the men who interrogated 9/11 mastermind Khalid Sheikh Mohammad told Fox News' "The Kelly File" Wednesday that political correctness "started that chain" that led to Monday night's truck attack on a Berlin Christmas market.

"[It] was political correctness and their unwillingness to get this person out of their country who had no business being there because he didn’t have the right paperwork to prove who he was," said Dr. James Mitchell, referring to Anis Amri.

German authorities Wednesday named Amri as the suspect in the attack, which killed 12 people and injured 48 others, touching off a continent-wide manhunt.

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Mitchell said that he and Mohammed, commonly known as KSM, had discussed the damaging potential of smaller, "lone-wolf"-style attacks more than a decade ago. Mitchell noted that Mohammed had been particularly struck by the terror caused by the 2002 D.C. sniper attacks.

"For him, what surprised him was how much paralysis it caused given how few deaths were involved, few from his perspective," Mitchell told host Sandra Smith. "And what he said to me was our civil liberties and our openness and our willingness to be responsive to other peoples’ cultures ... were weaknesses and flaws that his God, Allah, had put into the American culture so that we could be defeated."

Mitchell added that Mohammed believed that the easiest way to win what he called "the long battle to take over the world with Sharia law" was through "through immigration and by outbreeding non-Muslims."

"He said that like-minded jihadi brothers would immigrate to Western democracies and to the United States, they would wrap themselves in our civil liberties for protection," Mitchell said, "they would support themselves in our welfare systems while they spread their jihadi message, and then, when the time was right, they would rise up and attack."

In response to the terror threat, Mitchell called for the U.S. to restrict immigration from countries that promote terrorism, adopting President-elect Donald Trump's proposal from the recent election campaign.

"I hope there’s gonna be change," Mitchell said of Trump's election, "because here’s the way political correctness works for a guy like Khalid Sheikh Mohammed: It allows them to operate in our midst without being challenged.