An executive security expert ripped Secret Service chief Kimberly Cheatle for failing to protect former President Trump on Saturday, saying the agency needs to clean house, especially after her "sloped roof" excuse. 

Bill Stanton, who has worked in the field for four decades, took aim at Cheatle's assertion that agents passed on manning a nearby roof used by shooter Thomas Crooks because it was sloped.

The would-be assassin climbed to the roof of the building and squeezed off several rounds that injured Trump and killed rally attendee Corey Comperatore. Two others were critically wounded.

"Her explanation that it was dangerous that the roof was pitched to me is the equivalent of a school child saying that the dog ate their homework," Stanton said. "How does that pass muster for anybody, regardless of political affiliation?"