People in Washington have advice for those guarding the White House.

Lock the door, said a US congressman, Mike Rogers, on CBS's Face the Nation.

On Friday, a man later identified as Iraq War veteran Omar Gonzalez climbed a fence, ran more than 60m (197ft) and made it through the North Portico door.

One former Secret Service officer who asked not to be identified ("I'm a private person," he says) is as puzzled as anyone about his former colleagues - and "how hapless they seemed".

He says he's spent "many hours" standing at the North Portico door. He wonders how Gonzalez made it that far.

"I'm at a loss to explain why somebody didn't tackle him," he says.

Gonzalez was captured - once he got inside. He had a knife and 800 rounds of ammunition in a car parked blocks away, according to authorities.