The Biden administration is pushing out the most senior career official at the country’s largest law enforcement agency, U.S. Customs and Border Protection, according to two people with firsthand knowledge.

Political appointees at the Department of Homeland Security chose not to keep CBP Deputy Commissioner Robert Perez on as the second in command of the federal agency. Perez was promoted to his position at CBP headquarters in Washington in July 2018 and oversaw operations of trade, travel, immigration, and national security at land, air, and sea borders.