A New York City investigator violated sanctuary laws that limit information sharing between local officials and the federal government by providing details about two immigrants held in city jails, according to a report released by a city watchdog agency on Thursday.

The report found that a Department of Correction investigator provided information about two detainees to Department of Homeland Security agents on two occasions, in late 2024 and in February 2025, helping federal officials arrest one of the detainees after his release from jail.

In February, the investigator provided federal agents with real-time information about the release of the detainee, Cristian Concepcion, a Venezuelan man who had been convicted of third-degree assault, a misdemeanor, and was being held at the Rikers Island jail complex.

The information helped federal agents detain Mr. Concepcion shortly after he got off a bus exiting Rikers Island on Feb. 3. He was charged with entering the country illegally and was sent to a federal immigration detention center, the report said. Federal agents did not present a formal request for his transfer or a judicial warrant, which are typically required under sanctuary laws for city officials to assist federal authorities, the report said.

Though the 68-page report, issued by the Department of Investigation, was narrowly focused on the actions of one investigator, whose mistakes were cast as unintentional, it blamed the administration of Mayor Eric Adams for not properly training jail officials on how and when they can share information about noncitizens with immigration authorities.

The report found that the investigator, who worked closely with federal agents on a task force focused on violent gangs, was unaware that the assistance he was providing was largely prohibited under the sanctuary laws. His assistance would have been allowed in a criminal investigation.