Jan. 6th 2021 - Capitol Police open the doors and let rally-goers walk into the capitol

Capitol Police open the doors and let rally-goers walk into the capitol.
How come they let the people get in?
Who gave the orders to open the doors?
Was the Speaker of the House (Pelosi at the time) in charge?
Who is the head of security at the capitol? 🤔🤔🤔