https://www.heritage.org/constitution?essay_id=10000025
The Heritage Guide to the Constitution
Privilege from Arrest
ARTICLE I, SECTION 6, CLAUSE 1
The Senators and Representatives…shall in all Cases, except Treason, Felony, and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same….
I screenshot it to a PDF file for archiving