Mayor Eric Adams appointed a former FBI agent as acting NYPD commissioner after Edward Caban resigned on Thursday amid a sprawling federal investigation into the mayor’s inner circle.

An hour after Caban announced his resignation in an email to the nation’s largest police department, Adams took the stage at a news conference to announce Thomas Donlon as acting head of the NYPD.

Donlon worked as chief of the FBI’s National Threat Center, and as New York’s director of the Office of Homeland Security, Adams said. He also ran the FBI-NYPD Joint Terrorist Task Force. Donlon currently works as chairman of the BlackRock Investment Institute. A Bronx native, he is the co-founder and CEO of a private security firm called Global Security Resolutions.

The appointment is a departure from the NYPD’s typical process of promoting from within. When former police commissioner Keechant Sewell stepped down last summer, Caban — then-first deputy commissioner — was appointed to the top seat.