In an interview on “The Hugh Hewitt Show” that aired Monday morning, former President Donald Trump criticized Vice President Kamala Harris for her policies on the southern border and suggested that migrants have “bad genes.”

“When you look at the things that she proposes, they’re so far off she has no clue. How about allowing people to come to an open border, 13,000 of which were murderers,” he said, referring to the vice president’s immigration proposals.

“Many of them murdered far more than one person, and they’re now happily living in the United States,” he added. “You know, now a murderer, I believe this, it’s in their genes. And we got a lot of bad genes in our country right now. They left, they had 425,000 people come into our country that shouldn’t be here, that are criminals.”

NBC News has reached out to the Trump campaign for further clarification.

The 13,000 figure Trump cited is misleading. Immigration and Customs Enforcement told Congress in September that there are 13,000 immigrants convicted of homicide living outside of ICE detention, but three law enforcement officials told NBC News that that figure doesn't include people who were detained outside of ICE enforcement because ICE doesn't keep track of incarcerations on the state or local level. Two law enforcement officials also told NBC News that many of them crossed the border before Biden was president (including during Trump's tenure).

Border crossings across the country have dropped this year, in part due to Biden administration policies and in part to Mexico's efforts (which followed pressure on the Mexican government from the Biden administration).

During a rally last month, Trump argued that Harris should be “impeached and prosecuted,” suggesting that her border policies have led to people being murdered by migrants who crossed the border. Trump and his allies have sought to blame Harris for millions of border crossings by migrants after Biden in 2021 deputized her to address the root causes of migration from Central America.

Trump has long invoked disparaging rhetoric when discussing immigration. He launched his 2016 presidential campaign by complaining about Mexico “not sending the best” people. His comments have ramped up since then, accusing immigrants of "poisoning the blood of our country," a phrase that the Biden campaign likened to Adolf Hitler and drew rebuke from Republican lawmakers.

This isn’t the first time that Trump has invoked race science. In 2020 he praised a nearly all-white crowd at a rally in Minnesota for having “good genes,” pointing to a belief that has been touted by white supremacists called “racehorse theory.”

“You have good genes. You know that, right? You have good genes. A lot of it is about the genes, isn’t it, don’t you believe? The racehorse theory. You think we’re so different? You have good genes in Minnesota,” Trump said at the 2020 rally.