An intruder armed with a
knife managed to dodge guards and enter the White House because of poor
communication and a series of lapses, a report has found.
Omar Gonzalez jumped over the fence in September, ran past guards and was only stopped deep inside the building.An official US inquiry says Secret Service agents - including one with an attack dog - did not react on time or in the right manner.
The Secret Service chief resigned, partly as a result of this breach.
Julia Pierson stepped down after details emerged of this incident, and of previous breaches in the security surrounding the president.
The latest findings about the September incident are part of a broader inquiry into the lapses, led by the Department of Homeland Security.
According to The New York Times, an executive summary of the inquiry released on Thursday night said the blame for the breach lay with "performance, organisation and technical" failures.
The report described in detail how agents had missed a series of opportunities to stop Mr Gonzalez - on the evening of the intrusion as well in the run-up to it.
Mr Gonzalez scaled the fence at a point where a spike was missing, the report said.
Many officers at a gate on Pennsylvania Avenue did not have a clear view of him because of a construction project.
An officer with an attack dog on the White House driveway was using his mobile phone at the time, and did not hear warnings on his radio earpiece, or on another radio, which had been stashed away in a locker.
Two officers who were pursuing Mr Gonzalez did not expect him to pass through thick bushes, which he did.
Once inside the building, the report said Mr Gonzalez was able to push past a female officer, who was smaller than him and who had accidently reached for her torch instead of a metal baton.
He was eventually tackled in the East Room, a long, ornately-decorated chamber used for presidential addresses and formal receptions.
Early on in the intrusion, warnings were not relayed properly to agents inside the White House building because alarm systems and radios failed to function as intended.
He was stopped in Virginia in July. Then, officers found two powerful rifles, four handguns and other firearms and ammunition in his vehicle along with a map marking the White House.
Mr Obama and his family were not at the White House when the intrusion happened, having departed about 10 minutes earlier by helicopter.
Mr Gonzalez has been indicted on charges including unlawfully entering a restricted building or grounds while carrying a deadly or dangerous weapon and unlawful possession of ammunition.
The intrusion came after a series of embarrassing lapses by the Secret Service - including reports that agents had used prostitutes while on duty in Colombia.
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