The New York Police Department is investigating why officers gave U.S. authorities the sealed arrest record of a New Jersey woman who was detained at a protest last year — information that immigration officials are now using to seek her deportation.

Under New York State law and department policy, sealed records of arrests or summons cannot be released. But the police gave the documents to Department of Homeland Security investigators who had requested them as part of what the investigators said was a criminal investigation, Commissioner Jessica Tisch and the woman’s lawyer said on Tuesday.

The documents, the lawyer said, then became part of the government’s case for deporting the woman, Leqaa Kordia, 32, who is Palestinian.

The case, first reported by The Associated Press, emerged as the Trump administration pressured Mayor Eric Adams to cooperate with its deportation campaign. Commissioner Tisch has repeatedly said that New York’s sanctuary laws bar police officers from cooperating with federal officials on immigration cases, which are considered civil violations.

Ms. Kordia, who does not have a valid visa, was arrested during a protest in April 2024, when scores of demonstrators gathered at Columbia University to protest the war in Gaza.

On Tuesday, Commissioner Tisch said at a City Hall news conference that an official from Homeland Security Investigations in New Jersey had asked for information about Ms. Kordia, saying that she was being investigated in connection with money laundering.