with night falling, rein reinforcement finally arrived to flush out the rioters. >> wolf, we are on the western side of the capitol. you can hear a flashbang presumably from this police force that has just moved in. what you're looking at now is metropolitan police from washington, d.c., who, just before this 6:00 p.m. curfew, have moved in here to push out the rioters. they have been shouting "move back" at this crowd of hundreds if not more trump supporters on the western side of the capitol building. >> reporter: many felt victorious, their message heard. several dozen were arrested, by hundreds more slipped into the night away from the police. a relatively quiet end to one of the most dramatic and dark days in american history. kate, in the days that followed the insurrection, the fbi launched what would become its biggest investigation ever.