Americans want answers about the assassination attempt on President Trump, but the Secret Service isn't in a hurry.

The agency's embattled director, Kimberly Cheatle, has delayed a congressional briefing about Saturday's shooting in Butler, Pennsylvania.

The House Homeland Security Committee was supposed to hear from the Secret Service on Monday, but the agency postponed the virtual briefing, citing Cheatle's presence at the Republican National Convention in Milwaukee.

“The committee has made clear that it expects to receive an alternative briefing date from the [Secret Service] promptly,” a panel spokesman told the New York Post.  

Secret Service under scrutiny

Many Americans want to know why the Secret Service did not secure a rooftop that gave the shooter a clear shot at Trump from just 150 yards away.

The Secret Service has said local police were responsible for the area outside the agency's security perimeter. But it's unclear why such a close and obvious vantage point wasn't part of the security perimeter to begin with.

A bullet nearly killed Trump but instead struck his right ear. Gunman Thomas Matthew Crooks killed 50-year-old rallygoer Corey Comperatore and left two others critically injured.

In an ABC News interview Tuesday, Cheatle brought more backlash when she blamed the rooftop's "sloped" surface.

"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 said.

Pointing the finger

A local officer confronted Crooks moments before the shooting, but the cop dropped down to avoid being shot. The officer retreated because he was not able to draw his weapon, according to Butler County Sheriff Michael Slupe.

While Secret Service blames local police for the security breakdown, Patrick Yoes, the national president of the Fraternal Order of Police, says the failures started at the top.

"This is a failure at the management or command level who failed to secure an obvious weakness in the security of this event," Yoes said.

In her ABC interview, Cheatle said "the buck stops with me" but she hasn't committed to stepping down.

Cheatle has a public hearing next Monday. Secret Service also had a closed-door briefing with lawmakers Tuesday.

Enough lies. America wants answers for this disaster.