U.S. Secret Service Director Julia Pierson resigned Wednesday afternoon following fallout over recent security breaches around the White House. The scrutiny came after a man jumped a White House fence on Sept. 19 and made it far into the Executive Mansion with a knife.

Secretary of Homeland Security Jeh Johnson said in a statement that "scrutiny by a distinguished panel of independent experts of the September 19 incident and related issues concerning the Secret Service is warranted," and that a panel will submit findings by Nov. 1.

Pierson started with the Secret Service in 1984 and became director in March of last year. She was also criticized over a 2011 incident in which a man fired shots that hit the White House. A Secret Service team took days to discover the shooting.