How did pro-Donald Trump protesters get into Washington DC’s heavily guarded Capitol building?

Donald Trump supporters in Washington DC broke into the Capitol building, attacking police, smashing windows and knocking down doors as Congress was expected to vote to affirm Joe Biden’s 2020 presidential win.

Rioters made it into the House Chambers, where US lawmakers had to be evacuated, and also into the offices of some officials.

So how did they get pass heavily-guarded police and into the building?

Some Capitol police let people through barricades

Remarkable vision emerged online of police opening barricades to let people walk towards Capitol Hill.