While immigration officials have used the tech for years, an October letter from the Department of Homeland Security obtained exclusively by The Associated Press details how those tools — some of them powered by AI — help make decisions over whether an immigrant should be detained or surveilled.

One algorithm, for example, ranks immigrants with a “Hurricane Score,” ranging from 1-5, to assess whether someone will “abscond” from the agency’s supervision.

The letter, sent by DHS Chief Artificial Intelligence Officer Eric Hysen to the immigrant rights group Just Futures Law, revealed that the score calculates the potential risk that an immigrant — with a pending case — will fail to check in with Immigration and Customs Enforcement officers. The algorithm relies on several factors, he said, including an immigrant’s number of violations and length of time in the program, and whether the person has a travel document. Hysen wrote that ICE officers consider the score, among other information, when making decisions about an immigrant’s case.

“The Hurricane Score does not make decisions on detention, deportation, or surveillance; instead, it is used to inform human decision-making,” Hysen wrote.

Also included in the government’s tool kit is a mobile app called SmartLINK that uses facial matching and can track an immigrant’s specific location.

Nearly 200,000 people without legal status who are in removal proceedings are enrolled in the Alternatives to Detention program, under which certain immigrants can live in the U.S. while their immigration cases are pending.

In exchange, SmartLINK and GPS trackers used by ICE rigorously surveil them and their movements. The phone application draws on facial matching technology and geolocation data, which has been used before to find and arrest those using the app.

Just Futures Law wrote to Hysen earlier this year, questioning the fairness of using an algorithm to assess whether someone is a flight risk and raising concerns over how much data SmartLINK collects. Such AI systems, which score or screen people, are used widely but remain largely unregulated even though some have been found to discriminate on race, gender or other protected traits.

DHS said in an email that it is committed to ensuring that its use of AI is transparent and safeguards privacy and civil rights while avoiding biases. The agency said it is working to implement the Biden administration’s requirements on using AI, but Hysen said in his letter that security officials may waive those requirements for certain uses. Trump has publicly vowed to repeal Biden’s AI policy when he returns to the White House in January.

“DHS uses AI to assist our personnel in their work, but DHS does not use the outputs of AI systems as the sole basis for any law enforcement action or denial of benefits,” a spokesperson for DHS told the AP.

Trump has not revealed how he plans to carry out his promised deportation of an estimated 11 million people living in the country illegally. Although he has proposed invoking wartime powers, as well as military involvement, the plan would face major logistical challenges — such as where to keep those who have been detained and how to find people spread across the country — that AI-powered surveillance tools could potentially address.

Karoline Leavitt, a spokesperson for Trump, did not answer questions about how the incoming administration plans to use DHS’ tech, but said in a statement that “President Trump will marshal every federal and state power necessary to institute the largest deportation operation” in American history.

Over 100 civil society groups sent a letter on Friday urging the Office of Management and Budget to require DHS to comply with the Biden administration’s guidelines. A spokesperson for OMB said that agencies must align their AI tools with the guidelines by December 1, and that any extensions or waivers of that deadline will be publicly disclosed next month.

Just Futures Law’s executive director, Paromita Shah, said if immigrants are scored as flight risks, they are more likely to remain in detention, “limiting their ability to prepare a defense in their case in immigration court, which is already difficult enough as it is.”

SmartLINK, part of the Intensive Supervision Appearance Program, is run by BI Inc., a subsidiary of the private prison company The GEO Group. The GEO Group also contracts with ICE to run detention centers.

ICE is tight-lipped about how it uses SmartLINK’s location feature to find and arrest immigrants. Still, public records show that during Trump’s first term in 2018, Manassas, Virginia-based employees of BI Inc. relayed immigrants’ GPS locations to federal authorities, who then arrested over 40 people.

In a report last year to address privacy issues and concerns, DHS said that the mobile app includes security features that “prohibit access to information on the participant’s mobile device, with the exception of location data points when the app is open.”

But the report notes that there remains a risk that data collected from people “may be misused for unauthorized persistent monitoring.”

Such information could also be stored in other ICE and DHS databases and used for other DHS mission purposes, the report said.

On investor calls earlier this month, private prison companies were clear-eyed about the opportunities ahead.

The GEO Group’s executive chairman George Christopher Zoley said that he expects the incoming Trump administration to “take a much more aggressive approach regarding border security as well as interior enforcement and to request additional funding from Congress to achieve these goals.”

“In GEO’s ISAP program, we can scale up from the present 182,500 participants to several hundreds of thousands, or even millions of participants,” Zoley said.

That same day, the head of another private prison company told investors he would be watching closely to see how the new administration may change immigrant monitoring programs.

“It’s an opportunity for multiple vendors to engage ICE about the program going forward and think about creative and innovative solutions to not only get better outcomes, but also scale up the program as necessary,” Damon Hininger, CEO of the private prison company CoreCivic Inc. said on an earnings call.

GEO did not respond to requests for comment. In a statement, CoreCivic said that it has played “a valued but limited role in America’s immigration system” for both Democrats and Republicans for over 40 years.