Biden's Secret Service Director Kimberly Cheatle faces lawmakers demanding answers on Trump assassination attempt

Secret Service Director Kimberly Cheatle will face a barrage of questioning Monday morning as lawmakers seek answers on how the biggest Secret Service breach in four decades took place under her watch. 

Monday's hearing marks the first time the public will hear extensively about what happened from Cheatle under questioning from the House Oversight Committee. 

Since the July 13 shooting, she's done no press conferences and very few interviews, but has insisted she will not resign. 

Comer said on Fox News Sunday the hearing would go on for six hours and Cheatle would face 'hundreds of questions.' 

'The Secret Service has thousands of employees and a significant budget, but it has now become the face of incompetence,' Comer will say at the hearing, according to his opening remarks obtained by DailyMail.com. 

Last Saturday, 20-year-old Thomas Crooks shot multiple rounds at Donald Trump, clipping his ear, injuring multiple attendees and tragically killing former firefighter Corey Comperatore at the Butler, Pa. rally. 

And last week, lawmakers were given a private briefing by Secret Service where they learned the shooter had been spotted about an hour before he fired his first shot.

Even more troubling, Secret Service counter-snipers saw Crooks on the roof 20 minutes before he shot the former president. 

Trump walked out onto the stage at 6:02 p.m.

Then at around 6:12 p.m. Crooks' first shots rang out.

 Cheatle could not tell lawmakers how the shooter had gotten onto the roof.

At the time of the shooting, law enforcement agents were inside the building, 147 yards away from where Trump stood, but not on top of it. 

Cheatle curiously claimed no officers had been placed on the roof because it was sloped. 

'That building in particular has a sloped roof at its highest point. And so, you know, there's a safety factor that would be considered there that we wouldn't want to put somebody up on a sloped roof,' she told ABC News in an interview Tuesday.

'And so, you know, the decision was made to secure the building, from inside.'

What transpired instead was a security nightmare: Thomas Matthew Crooks was able to scale the building and secure his own position, while law enforcement struggled to locate him even amid pressing warnings from members of the Trump crowd. But there wasn't sufficient time to act on the tips, she explained.

'The shooter was actually identified as a potential person of suspicion,' Cheatle said. 'Unfortunately, with the rapid succession of how things unfolded, by the time that individual was eventually located, they were on the rooftop and were able to fire off at the former president.'

She was referencing claims by witnesses that they alerted law enforcement about the threat, but agents weren't able to eliminate the threat in time. Officials have pointed to the initial responding officer, who lifted himself up on the roof only to lower himself back when the gunman turned his weapon at him. 

Cheatle has take blame for the fateful security breach, but has denied calls to step down. 

'The buck stops with me,' she said.

'It was unacceptable,' she told ABC. 'And it's something that shouldn't happen again.'

'While we give overwhelming thanks to the individual Secret Service agents who did their jobs under immense pressure, this tragedy was preventable. The Secret Service has a zero fail mission, but it failed on July 13 and in the days leading up to the rally,' Comer is also expected to say, as he will again call for Cheatle's resignation.  

Also coming into question on the call was the possible motive for Crooks to commit such an atrocity.

Officials did not confirm an operating motive and said that his rationale remains a mystery. 

Authorities said that they have yet to find any ideological material that could shine light on why Crooks decided to shoot the former president.

But, they did reveal that Crooks operated several accounts on encrypted platforms that they are still working to gain access to.