CNN senior White House correspondent Jim Acosta on Wednesday revealed what the thought was “part of the reason” Secret Service director Julia Pierson resigned.

“This all happened very quickly obviously, because, in part because of her testimony yesterday,” he said, speaking on the cable news network. “I talked to a number of people up on Capitol Hill. Aides to various congressman on Capitol Hill and to people inside the administration who just felt that her testimony was not inspiring.”

“It was not reassuring and that was part of the reason for her departure,” Acosta added

Pierson resigned from her post in the afternoon, just one day after facing heavy criticism during a hearing on Capitol Hill about multiple security lapses that posed safety risks for the president.