Aaron C. DavisVerified account

Among our findings: Although President Trump, Attorney General Barr and federal law enforcement agencies have denied that tear gas or chemical agents were used against protesters. The Post found city streets were swept the night before, and new CS canisters were found after.

Riot teams from the federal Bureau of Prisons, which are trained to subdue unrest at federal penitentiaries, were involved in the police offensive. Video evidence show they shot into the crowd of fleeing protesters.

Police agencies employed a new tactic: rushing at protesters to scare them into fleeing. It was a move developed in response to the Freddie Gray riots in Baltimore in 2015. But many officers on the scene had never used it, and DC-area agencies had only trained together on it once

And there was little evidence of provocation for the police action: The Post could not find any video confirmation that rocks, bricks, or caustic liquids had been thrown on police, as the U.S. Park Police alleged the following day in explaining the offensive.

Conversely, video shows law enforcement and military personnel under tactical command of the U.S. Park Police fired riot-control grenades packed with chemical irritants, 'stinger' grenades that send rubber pellet spraying 50-yards, flash-bangs, smoke bombs, and pepper balls.

Over the last week, the White House, President Trump, AG Barr and others have offered shifting explanations for why the offensive was needed, and at that moment -- shortly before a surprise visit by Trump to the center of the protest area. Most do not stand up to scrutiny.

1. The morning after, Trump cheered the show of force, tweeting: “D.C. had no problems last night... Overwhelming force. Domination.” The WH also asserted the crowd was dispersed to enforce DC's 7 p.m. curfew. But DC did not ask for help, and the curfew hadn’t yet taken effect.

2. WH spokeswoman Kayleigh McEnany told reporters Wednesday that Barr made the decision to push back the security perimeter, and he was surprised it hadn’t been done when he arrived for Trump’s press conference. Barr “said that we needed to get going with moving that perimeter."

Barr told the AP something else on Friday, saying he did not give the “tactical” command to disperse the crowd, though he supported the decision.

3. In recent days, Barr and Park Police have added another explanation, saying that officers’ offensive Monday must be viewed in light of the preceding days of protests, especially because 51 officers had been injured over in the days beforehand.

Responding to 24 pages of questions and timeline highlights, Park Police told The WashPost: “Your timeline doesn’t take into account increasing violence leading up to and during the timeframe you’ve suggested. During four days of demonstrations, 51 members of USPP were injured."

Barr added Sunday in an interview with CBS: "It wasn't a peaceful protest. We had to get control over Lafayette Park, and we had to do it as soon as we were able to do that." He also reiterated that the main reason for the operation was to push back the security perimeter.

Many public safety and military officials question that. Longtime U.S. Capitol Police Chief Terrance Gainer told The Post that if the justification was moving a security perimeter - something done often in D.C. - it should have been done before dawn when crowds were gone:

“There was no reason to use force and fight, it wasn’t necessary. If they wanted to clear that park, they could have done it in a very orderly way, giving people notice. There just wasn’t exigent circumstances. There was no indication that the demonstration was turning dangerous”