6:58 PM PT -- Reps for CBS tell TMZ ... "On Wednesday, June 15 and Thursday, June 16, Triumph the Insult Comic Dog was on-site at the Capitol with a production team to record interviews for a comedy segment on behalf of 'The Late Show.'"
"Their interviews at the Capitol were authorized and pre-arranged through Congressional aides of the members interviewed."
"After leaving the members’ offices on their last interview of the day, the production team stayed to film stand-ups and other final comedy elements in the halls when they were detained by Capitol Police."
Several staffers from Stephen Colbert's late night CBS talk show got busted at the U.S. Capitol ... after they allegedly made an unlawful entry into the building.
Robert Smigel, the voice of Triumph the Insult Comic Dog, was among the 9 people arrested by U.S. Capitol Police and charged with illegal entry ... according to Fox News.
The "Late Show With Stephen Colbert" staffers were arrested after taking pictures and videos near the offices of House Minority Leader Kevin McCarthy and Rep. Lauren Boebert.