The sharpshooters on the roof with their sniper scopes didn’t kill the intruder racing towards the White House. The handlers on the North Lawn didn’t unleash the powerful, unmuzzled dogs trained to take down any assailant. The armed agents, inside the grounds and outside among the tourist throngs on Pennsylvania Avenue, didn’t shoot. The White House doors weren’t locked. And the US Secret Service agent inside the imposing main White House entrance was apparently so surprised when Omar J. Gonzalez burst in that he was able to just knock her aside.

No agent was stationed at the stairs leading to the first family’s private quarters when Gonzalez ran past, deep inside one of the world’s supposedly most secure buildings. Finally, an off-duty Secret Service officer tackled the intruder, who had a knife in his pocket, in the East Room.

Explanations and excuses are now pouring forth from Julia Pierson, who heads the $1.8-billion, 6,700-person Secret Service which, despite other missions from tracking counterfeiters to guarding foreign dignitaries, has as its primary purpose protecting the President of the United States.

An inquiry continues into how Omar Gonzalez, 42, made it into the White House. Investigators are looking through an elaborate closed-circuit video system showing the entire incident. Authorities said the Iraq war veteran had a knife in his pocket when he ran into the White House, where he was later subdued after a wild chase.

Neither President Barack Obama nor the first family were at home at the time of the incident on September 19.

Julia Pierson, the first female director of the Secret Service, after a subsequent congressional inquiry uncovered other security lapses and submitted her resignation. Pierson took over as director of the Secret Service in March 2013.

After her resignation, Homeland Security Director Jeh Johnson announced that his department would take over an internal inquiry of the Secret Service and appoint a new panel to review security at the White House.

Joseph Clancy, a former special agent in charge of the Presidential Protective Division of the Secret Service, will serve as interim director, Johnson said.