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.

Ms. Kordia’s lawyer said later that the commissioner’s statement was the first that he or his client had heard of such an investigation.

Commissioner Tisch said that while the city’s sanctuary laws bar it from helping immigration authorities in civil deportation cases, criminal investigations are a different matter. The Police Department handed over information, “which was all done according to procedure,” she said, without specifying precisely what was transmitted to federal investigators.

“That is definitely an instance where we would share information,” she said, adding that department officials would look into how the summons record that was part of a sealed case was also provided.

Arthur Ago, a lawyer at the Southern Poverty Law Center who represents Ms. Kordia, said that she was born in Jerusalem and raised on the West Bank. She went to the protest at Columbia to mourn relatives killed during the war in Gaza, he said.

At the protest last year, Ms. Kordia was given a summons for disorderly conduct, Mr. Ago said. The case was dismissed shortly after, he said, and she was not charged with other violations.

After the arrest, Ms. Kordia returned to New Jersey, where she had been trying to start a business selling candles and small gifts. It was unclear when immigration authorities began building a case against her.

On March 13, Immigration and Customs Enforcement agents in New Jersey arrested Ms. Kordia. She was put on a plane and sent to Prairieland Detention Facility in Alvarado, Texas, where she is fighting deportation, Mr. Ago said.

The following day, an officer who works at the Police Department’s Real Time Crime Center, a hub that provides detectives with data, gave Homeland Security a four-page report that had been sealed. Ms. Kordia had been standing with about 100 other protesters, blocking a gate on campus, according to the report, which said she had no record of criminal complaints or investigations.

Mr. Ago said that he learned that federal officials had the report about his client’s protest arrest when he reviewed Ms. Kordia’s immigration case file. Mr. Ago said that Ms. Kordia had posted nothing on social media and her arrest was not publicized, he said, raising questions about how federal officials had learned about her.

Mr. Ago said in a statement that the Homeland Security Department “has never communicated to us or indicated in court that Ms. Kordia is under investigation for money laundering.”

“The allegation comes as a complete surprise, is entirely unfounded, and we categorically deny it,” Mr. Ago said. “We are prepared to fight this allegation in court.”

Mr. Ago said that federal officials had submitted documents in immigration court describing Ms. Kordia as “a low risk of danger and a low risk of flight.” But during proceedings, lawyers for the federal government described her as a danger, though they did not provide details, Mr. Ago said.

Homeland Security and ICE officials did not respond to repeated requests for comments Tuesday.

The case suggests that the Trump administration is using the pretext of criminal investigations to speed deportations, said Peter L. Markowitz, an immigration law professor at the Cardozo School of Law who helped draft the city’s sanctuary laws.

He said it is proper for the Police Department to share information with federal authorities about criminal investigations that are not related to immigration enforcement. But he said that the Trump administration’s actions mean that requests cannot be taken at face value.

“Given the Trump administration’s track record of playing fast and loose with facts to skirt legal constraints, it is incumbent on the Police Department to do more in the future to confirm that they are not illegally entangled in Trump’s mass deportation programs,” Mr. Markowitz said.

The administration has aggressively pursued people who have participated in Gaza protests at campuses.

Ms. Kordia arrived in the United States in 2016 on a tourist visa, Mr. Ago said, but began taking classes to improve her English and was granted a student visa within a year.

Soon after, Ms. Kordia’s mother, a naturalized U.S. citizen, petitioned for an I-130 visa — a document that would establish that Ms. Kordia was her daughter and pave the way toward citizenship, Mr. Ago said.

But in 2022, Mr. Ago said, Ms. Kordia got bad advice from a school official who told her she could drop her student visa, because she had received a notice that her I-130 application had been approved.

That move left her without a valid visa, Mr. Ago said. It is on that basis that immigration officials have moved to have her deported, he said.

In March, Department of Homeland Security officials knocked on the front door of Ms. Kordia’s home in New Jersey, Mr. Ago said. They spoke to her mother, who immediately called Ms. Kordia at work, Mr. Ago said.

Ms. Kordia spoke over the phone with the officials, who told her to come the following week to their office. They did not say what they wanted, but Ms. Kordia called a lawyer who agreed to come with her, Mr. Ago said.

When Ms. Kordia appeared at the office on March 13, officials told her lawyer to sit in the hallway while they spoke with her. Soon after, they told the lawyer that Ms. Kordia was being detained.

Maia Coleman contributed reporting.