Immigration and Customs Enforcement provides its agents with information about how to use material that the National Security Agency obtains through its spy programs, according to documents obtained by The Daily Beast through a Freedom of Information Act request.

With assistance from the James Madison Project, The Daily Beast obtained a heavily redacted chapter from a handbook for agents in ICE’s Homeland Security Investigations component. The chapter gives those agents an overview of how the Foreign Intelligence Surveillance Act works.

That may not sound like a big deal. But it indicates that NSA surveillance is relevant to the immigration agency’s work.

“FISA allows for the retention and dissemination of information that is evidence of a crime and is being retained or disseminated for law enforcement purposes,” the handbook says.

A paragraph on the uses of foreign intelligence information is redacted, as is an entire section titled “FISA Authority vs. Court-Overseen Criminal Investigatory Surveillance Techniques.”

A significant portion of a section about surveilling people suspected of being “lone wolf” terrorists.

ICE provided this information in response to a query from The Daily Beast specifically asking for information related to how the agency uses information obtained through surveillance under the Section 702 program, which authorizes surveillance without a particularized warrant, as the Council on Foreign Relations has detailed. None of the unredacted portions of the document we obtained referred to Section 702, which may indicate that redacted portions did refer to it.

ICE did not provide additional comment or information on the agency’s use of intelligence information for this story.

Patrick Toomey, an attorney for the ACLU’s National Security Project, told The Daily Beast these documents raise privacy concerns.

“The document strongly suggests that private information obtained using the government’s secret spying tools is bleeding into certain ICE investigations,” Toomey said. “These tools were designed for foreign intelligence investigations, not immigration purposes. We need to know far more about how DHS agents use this sensitive information, what consequences it has for people living here in the United States, and when the government believes it must tell individuals that it has used FISA surveillance in immigration matters.”

ICE has two major components: Homeland Security Investigations (HSI), which includes the foreign surveillance information in its handbook, and Enforcement and Removal Operations (ERO). The latter component is the best known piece of the agency, as it is responsible for arresting, detaining, and deporting undocumented immigrants.

Homeland Security Investigations, on the other hand, works more like a traditional law enforcement agency. Its agents investigate a host of crimes, including child exploitation, human trafficking, and even art theft. It also conducts joint operations with ERO focused on gangs and transnational criminal groups. Though those operations focus on specific targets, they often result in the arrest of undocumented immigrants who aren’t suspected of crimes or gang affiliation.

So the documents raise plenty of questions: What safeguards are in place to protect people’s privacy, and how open will DHS be about its relationship to the NSA?