Courtney Burgess, a one-time music industry bit player, said he had videos showing encounters involving celebrities. Prosecutors recently subpoenaed him.

In Ms. Bondi, who served on his legal team during his first impeachment, the president-elect turned to a loyal ally to put his stamp on a Justice Department that he sees as hostile to him.

The celebrated broadcaster, who started at the New York station in 1974, announced that he would wrap up his anchoring career on Dec. 12.