F.B.I. Raids Headquarters of the N.Y.P.D. Sergeants’ Union

Federal investigators on Tuesday morning raided the Manhattan office of one of New York City’s main police unions in connection with an ongoing investigation, according to two people with the knowledge of the matter.

The union, the Sergeants Benevolent Association, represents about 13,000 active and retired police sergeants in New York. Its headquarters were searched as part of an investigation by the F.B.I. and the public corruption unit in the U.S. attorney’s office in Manhattan, the people said.

The focus and scope of the investigation, and whether other agencies were involved, could not immediately be determined. An F.B.I. spokesman said only that agents “were conducting a law enforcement operation pursuant to an ongoing investigation” at the union’s offices in Lower Manhattan.

The sergeants’ union, which says it is the fifth-largest police union in the country, did not immediately respond to a request for comment about the raid, which was reported earlier by The New York Daily News.

The union’s president, Edward D. Mullins, has become known for making brash and incendiary remarks on social media, particularly against Mayor Bill de Blasio.

Mr. Mullins recently faced internal discipline charges from the Police Department over his behavior on Twitter, including for sharing a police report documenting the arrest of Mr. de Blasio’s daughter, Chiara, during protests in New York.

The department does not typically release internal reports, and the one that Mr. Mullins shared contained personal information about Ms. de Blasio.

Mr. de Blasio declined to comment on the raid at a news conference on Tuesday, saying he did not know any details, but he said that Mr. Mullins had long been a “divisive voice” whose behavior had been “destructive.”