Donald Trump revealed an unhinged eugenics theory Monday, claiming during a morning rant that some migrants have “bad genes” that make them predisposed to committing murder.

Trump spent a good chunk of an interview on the The Hugh Hewitt radio show slamming the policies of his political opponent, Vice President Kamala Harris, and baselessly accused her of wanting to install a communist government.

“She wants to [do] government housing. She wants to go into government feeding. She wants to feed people. She wants to feed people governmentally,” he said as host Hugh Hewitt listened without saying a word. “She wants to go into a community party-type system. When you look at the things that she proposes, they’re so far off. She has no clue.”

Trump then attacked Harris’ handling of illegal immigration—despite her pushing back against his claims of a “crisis”—and alleged that she was letting people into the country with “bad genes.”

“How about allowing people to come to an open border, 13,000 of which were murders, many of them murdered far more than one person, and they are not happily living in the United States,” he said. “And now a murderer, I believe this, it’s in their genes.”

He added, “We got a lot of bad genes in our country right now.”

Throughout his presidential campaign, Trump has shown a fascination with genes—using the topic often during discussions of immigration to suggest some people are more superior than others.

During a 2020 campaign speech in Minnesota, Trump told a majority white crowd of his supporters that they have “good genes” and seemed to suggest that immigration and racism challenges in America comes down to genetic differences, reported the New York Times.

“A lot of it is about the genes, isn’t it, don’t you believe?” said Trump. “The racehorse theory, you think we’re so different? You have good genes in Minnesota.”