The American Civil Liberties Union of Maine has sued two federal agencies over an unfulfilled public records request related to citizenship checks at major transportation hubs.

The civil liberties organization asked federal officials in January to hand over records related to citizenship checks at two major transportation hubs in Maine. The request came after passengers boarding a Concord Coach bus at the Bangor Transportation Center were met by U.S. Customs and Border Protection agents asking about their citizenship.

In the months since, the organization has not received a response from Customs and Border Protection or its parent agency, the U.S. Department of Homeland Security. Now, the ACLU of Maine argues that the agencies have failed to respond to the request as required by the Freedom of Information Act, and the lawsuit seeks to compel the government to release the records.

“The public has the right to know how immigration agents are operating in our state,” staff attorney Emma Bond said in a statement. “Yet CBP has a long history of disregarding the law and ignoring public records requests.”

Jonathan Maynard, the public affairs liaison for the U.S. Border Patrol Houlton sector, said he is unable to comment on pending litigation.

Immigration inspections at transportation hubs are not a new practice. The Border Patrol, which is part of Customs and Border Protection, has the authority to conduct citizenship checks without a warrant within 100 miles of the nation’s land and coastal borders. That includes the entire state of Maine. Ten other states – Connecticut, Delaware, Florida, Hawaii, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island and Vermont – lie entirely or almost entirely in that 100-mile zone, the ACLU said.

No one on the Concord Coach bus in Bangor was arrested during the Jan. 14 inspection. Still, a passenger alerted the ACLU of Maine. The organization said there is evidence these inspections are becoming more frequent under the new enforcement priorities of the Trump administration. The sweeping Freedom of Information Act request seeks records from the past year related to citizenship inquiries at the Bangor and Portland transportation centers. It covers internal communications like text messages and emails, as well as reports or meeting minutes. The Portland Press Herald filed a similar request in February and has not received a response.

“We don’t have much more information about what is going on in Maine,” ACLU of Maine legal director Zachary Heiden said in January. “This Freedom of Information Act request is our way of trying to learn more about what Homeland Security is doing and why they’re doing it.”