Ex-border chief warns of 'significant threat' after migrant numbers skyrocketed under Biden-Harris admin

A retired border official is warning Americans about the increase in illegal immigration – especially of those considered "significant interest aliens" – as a result of the Biden-Harris border policies.

"There is a significant threat out there that we don't know," retired Chief Border Patrol Agent Aaron Heitke told "Fox & Friends First" Wednesday.

"We saw a steady increase in the number of individuals coming across the border… the numbers just continued to increase to the thousands and thousands each day."

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Heitke is testifying Wednesday before the House Homeland Security Committee over Biden-Harris administration policies that have resulted in over 8,200,000 migrant encounters at the southwest border from Feb. 2021–July 2024.

During his time in the San Diego sector, Heitke explained that he witnessed a staggering increase of migrants.

"In the last two years that I was in San Diego, San Diego averaged over the history of the sector – averaged 10 to 15 significant interest alien arrests per year," he said.

"In 2022, that jumped to well over 100. And in 2023, it was closer to 200. The numbers continue to skyrocket and that's just what we got."

Heitke added that in 2022 and 2023 there were "entire sectors" along the border across Arizona, Texas and California that at times had "no agent presence at all."

"We have no idea who and what came into our country over that time frame," he warned.

Heitke also shed light on the "struggle" to return migrants to their home countries.

"Many people don't realize that we have to have an agreement with each sending country to send their citizens back," Heitke said. "Those agreements were allowed to lapse… with the steady decrease in detention here, it comes down to release, and we end up just releasing those folks into the United States, which rather than deter them from coming, it encourages them to come." 

As a result, Heitke said during his time in San Diego, he encountered individuals "from many different criminal organizations and terrorist organizations." 

And he stressed that with fewer agents at the border, these individuals are able to cross into the U.S. and freely engage in dangerous activities ranging from fundraising for terrorism or cartels, narcotics, or human trafficking.

"Anything that they can make money on," according to Heitke. 

Additionally, a top House committee is doubling down on its efforts to get documents from the Biden administration about Vice President Kamala Harris’ role in what lawmakers call "the worst border crisis in American history."

House Oversight Committee Chair James Comer, R-Ky., wrote to acting Customs and Border Protection (CBP) Commissioner Troy Miller following up on a request last month for documents and communications between Harris’ office and CBP.

"The mass illegal entry and release of illegal aliens into the United States under the Biden-Harris Administration has contributed to murders, sexual assaults, and serious bodily injuries committed against numerous Americans at the hands of illegal aliens. These crimes should have never happened."

The letter notes a number of crimes more recently committed allegedly by illegal immigrants, including one by an MS-13 gang member and a rape in New York City, allegedly by two migrants.

Comer says the committee set an Aug 20., deadline, reiterating the request on Aug. 20 and Sept. 6. It now sets a deadline of Oct. 1 and Comer threatens additional action if the request is not met.

Fox News' Adam Shaw contributed to this report