From a story on politico.com by Myah Ward  headlined “Colbert staff detailed at Capitol after lawmaker interviews, charged with ‘unlawful entry'”:

Seven staff members of “The Late Show With Stephen Colbert” were charged with unlawful entry after being detained by U.S. Capitol Police following interviews with congressional lawmakers for a segment with Triumph the Insult Comic Dog.

The production team was at the Capitol Wednesday and Thursday recording the segment, according to CBS. The interviews were “authorized and pre-arranged” with the lawmakers being interviewed and their congressional aides.