President Joe Biden said a lot of Americans will learn new details about the Jan. 6 attack as lawmakers begin to reveal the findings of their 11-month investigation.

"One of the things that’s gonna occupy my country tonight, I suspect, is the first open hearings on January the 6th," Biden said as he sat down with Canadian Prime Minister Justin Trudeau at the Summit of the Americas on Thursday afternoon.

"And as I said when it was occurring and subsequent, I think it was a clear, flagrant violation of the Constitution," Biden continued. "I think these guys and women broke the law, tried to turn around the result of an election. And there's a lot of questions: who's responsible, who's involved?"

Thursday's hearing, the first of six scheduled in June, is the culmination of an 11-month-long investigation by the House select committee.

The nine-member panel has collected more than 140,000 documents and 1,000 witness interviews throughout the course of the investigation, and members have promised to introduce never-before-seen videos and exhibits they say will shock the public.

ABC News Television Network will air special coverage of the hearing at 8 p.m. and ABC News Live will carry gavel-to-gavel coverage.

The committee aired a video showing the moment Capitol Police officer Caroline Edwards was knocked out as she tried to hold the line from a crowd of rioters pushing up against barricades and bike racks.

Edwards winced as the video began.

"I felt the bike rack come on top of my head and I was pushed backwards, and my foot caught the stair behind me, and my chin hit the handrail," she said. "At that point I blacked out but the back of my head clipped the concrete stairs behind me."

Edwards returned to duty after regaining consciousness, saying "adrenaline kicked in" as she went to the West Front of the Capitol to protect the Senate steps. There she helped people who had gotten pepper sprayed and others injured before she was hit herself with pepper spray and tear gas.