In an unusual move, U.S. Customs and Border Protection checked the IDs of every passenger on a domestic flight before they were allowed to disembark at JFK airport on Wednesday night. A CBP spokesperson said later that they were searching for an undocumented person at the request of Immigration and Customs Enforcement, but they didn’t find that person on the flight.

According to Gothamist, when Delta Flight 1583 from San Francisco landed in New York around 8:30 p.m. there were customs agents stationed on either side of the door. As the plane landed, passengers were told to take out their “papers.”

“The head flight attendant came on and said, ‘Please have your papers ready’ three or four times,” said Matt O’Rouke of Manhattan. “Someone corrected her and she said, ‘Oh I mean photo IDs,’” he added. “To which people were kind of weirded out.”

O’Rouke said they studied everyone’s ID very carefully. “You could tell they weren’t just looking for a name. They read my entire ID and looked at me the entire time,” he said.

These are customs agents forcibly checking the ID of every passenger deplaning from Delta flight 1583 tonight at JFK. A domestic flight. pic.twitter.com/fHMgyzCjo5 — Britton Taylor (@brittontaylor) February 23, 2017

My flight from SFO to JFK. We were told we couldn't disembark without showing our "documents." pic.twitter.com/9ugQspTqeX — Anne Garrett (@annediego) February 23, 2017

Jordan Wells, a staff attorney with the New York Civil Liberties Union, told the Washington Post that law enforcement will sometimes board planes to search for a suspect, but the manner of the check seemed unusual.

“They’ll occasionally pull someone off of a flight, or officers will come on and make an arrest,” Wells said. “It’s a much more surgical thing than setting up a dragnet. That’s what is so alarming about the way that this played out.”

The Trump administration’s new immigration guidelines, which mostly eliminate priorities for deportation, have the undocumented community on edge, but it’s unclear if Wednesday’s search was related.

A CBP spokesman told Gothamist that the checks are “not a new policy” and it’s “not unusual for us to assist our fellow law-enforcement agencies.” The spokesman said they were searching for a person with criminal convictions for domestic assault, driving while impaired, and violating a protective order, and a judge had ordered that they be deported.