Bob Quinn, a former Mayer Brown trial attorney who has led AT&T Inc.’s lobbying team since 2016, has retired amid growing scrutiny over the $600,000 the telecom giant paid to Michael Cohen last year.

Quinn, executive vice president for external affairs and legislative affairs, ran the regulatory shop for state and federal operations and oversaw legislative efforts across the country. Previously, he led AT&T’s work before the Federal Communications Commission as the company’s senior vice president for regulatory affairs. In his first role at AT&T, as a vice president in the federal regulatory affairs group, he represented AT&T before not only the FCC but the U.S. Justice Department.