(AP Photo/Pablo Martinez Monsivais)
(AP Photo/Pablo Martinez Monsivais)

A House committee grilling the head of the Secret Service over the White Security breach.

FOX News Radio's Rachel Sutherland reports from Capitol Hill: 

(AP Photo/J. Scott Applewhite)
(AP Photo/J. Scott Applewhite)

Secret Service Director Julia Pierson says it's clear the department's security plan was not properly executed -- and she takes full responsibility for the security breach.

(Pierson) "I will make sure that it does not happen again."

And she promised:

(Pierson) "A complete and thorough investigation of the facts of this incident."

She vowed to make changes, including taking personnel action, after the investigation is complete. Lawmakers were shocked to find out Omar Gonzalez made it all the way to the doors of the Green Room. The Secret Service originally said he barely got into the front door.

At the Capitol, Rachel Sutherland, FOX News Radio.