NEW YORK (AP) — New York City’s interim police commissioner revealed late Saturday that federal authorities had executed search warrants at his homes.

Thomas Donlon, who became the interim commissioner just one week ago after the resignation of his predecessor, issued a statement on the search through the police department.

“On Friday, September 20, federal authorities executed search warrants at my residences. They took materials that came into my possession approximately 20 years ago and are unrelated to my work with the New York City Police Department,” the statement said.

“This is not a department matter, and the department will not be commenting,” he added.

The statement did not address what the investigation was about, which federal authorities were involved or what “materials” had been seized.

The unexplained and surprising search comes as the administration of New York City Mayor Eric Adams has been reeling from other federal law enforcement investigations.

Just a week ago, the previous police commissioner, Edward Caban, resigned after federal authorities seized his electronic devices as part of an investigation that also involved his brother, a former police officer.

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Federal agents also have seized phones from the head of the city’s public schools, a top deputy mayor, Adams’ top public safety adviser, and a year ago from the mayor himself.

Charges have not been brought in connection with any of those searches and it remained unclear whether there was any connection to the search involving Donlon, who wasn’t part of the Adams administration until a few days ago.

An FBI spokesperson declined to comment. An email seeking comment from a spokesperson for the U.S. attorney in Manhattan was not immediately returned. A text sent to Adams’ top spokesperson late Saturday night also wasn’t immediately returned.

Donlon spent decades with the FBI, where he worked on terrorism cases including the investigation into the 1993 bombing of the World Trade Center, the 1998 bombings of U.S. embassies in Kenya and Tanzania and a 2000 attack on a U.S. Navy destroyer.

Roughly 20 years ago he was a top counterterrorism official for the FBI in New York.

From 2009 to 2010, Donlon led New York state’s Office of Homeland Security before going into the private sector security industry.

Adams appointed Donlon as his commissioner last week and he assumed the post on Sept. 13, one week ago Friday.