WASHINGTON — The acting chief of the U.S. Drug Enforcement Administration is stepping down while the agency awaits the Trump administration’s nomination of its permanent leader.

A person familiar with the move said Chuck Rosenberg will leave the post Oct. 1. The person, who spoke to The Associated Press on condition of anonymity to discuss personnel matters, said Rosenberg notified employees of his decision in a short email Tuesday in which he thanked them for their hard work.

Rosenberg, a longtime ally of fired FBI Director James Comey, had been running the agency in a temporary capacity since 2015. He made news last month when he rejected President Donald Trump’s comments suggesting police shouldn’t be “nice” to suspects by shielding their heads as they are lowered, handcuffed, into police cars. He told employees the comment “condoned police misconduct” and reminded them drug agency’s operating principles, which include rule of law, respect and compassion and integrity.

The Trump administration has not nominated a replacement. But the person who spoke to AP said Col. Joseph Fuentes of the New Jersey State Police is a front-runner for the position. Fuentes had been a vocal critic of some Obama administration policies, including a deal reached in January between the U.S. and Cuba because it did not require the return of a woman convicted of killing a state trooper. A long time law enforcement officer, Fuentes pledged to work with Trump to secure her return.

The Washington Post first reported Rosenberg’s departure.