Three separate government whistleblowers familiar with the September 19 White House breach by a knife-wielding fence jumper revealed that the intruder made it far deeper into the presidential residence than the Secret Service originally admitted.

The Washington Post reported Monday that individuals familiar with the breach contacted the newspaper and the office of Republican representative Jason Chaffetz to provide details previously unreleased by the security agency. They allege that — contrary to the Secret Service’s official story — intruder Omar Gonzalez managed to make it much further than the unlocked front door.

At the request of the White House usher’s office, the alarm box designed to alert the officer at the front door to an impending intruder was muted, allowing Gonzalez to burst past the agent unopposed (the door was closed but unlocked). He then surged into the house’s central hall, passing a flight of stairs leading up to the First Family’s living quarters. He overpowered a female Secret Service agent who attempted to subdue him and allegedly made it across the East Room, before finally being tackled at the far end of that famous parlor by another officer.

The new information suggests the Secret Service’s failure earlier this month was even greater than expected, and that the agency may have been deceptive about the seriousness of the breach.

It’s not clear whether the agency notified the appropriate lawmakers about what the breach really entailed, but the Post report suggests that Chaffetz – despite being chairman of the House Oversight Committee’s national-security subcommittee – was not officially informed by the agency.

Secret Service director Julia Pierson will testify before the House Oversight and Reform Committee on Tuesday.