Omar Gonzalez, who breached security at the White House nearly two weeks ago, reportedly gained access to more of the presidential palace than previously believed.
Julia Pierson, the director of the secret service – the body charged with the president’s security – is to face questions about the intrusion.
US media now reports that Gonzalez scaled the perimeter fence and, armed with a knife, pushed past a guard at the door of the building before heading to the frequently-used East Room.
Only at this point was he tackled to the ground by authorities, unnamed officials are said to have told the media.
The Obama family were not in the house at the time.
Last week, a prosecutor said officers later found more than 800 rounds of ammunition, two hatchets and a machete in the 42-year-old’s car.
A decorated Iraq War veteran, Gonzalez had already been arrested in July with a sniper rifle and a map on which the White House was marked, the prosecutor told the court.