Article 1, Section 6, Clause 1
Document 20
Kentucky Constitution of 1799, ART. 2, SEC. 24
Thorpe 3:1280The members of the general assembly shall, in all cases, except treason, felony, breach or surety of the peace, be privileged from arrest during their attendance at the sessions of their respective houses, and in going to and returning from the same; and for any speech or debate in either house, they shall not be questioned in any other place.
The Founders' Constitution
Volume 2, Article 1, Section 6, Clause 1, Document 20
http://press-pubs.uchicago.edu/founders/documents/a1_6_1s20.html
The University of Chicago Press
Thorpe, Francis Newton, ed. The Federal and State Constitutions, Colonial Charters, and Other Organic Laws of the States, Territories, and Colonies Now or Heretofore Forming the United States of America. 7 vols. Washington, D.C.: Government Printing Office, 1909.