Complex sentence: It is rumored that when Clyde Barrow entered the Bank of Avilla, he looked Mr. Russell in the eye, and then saw his.45 strapped on while he sat behind the teller window.
Split into simpler sentences: It is rumored that Clyde Barrow entered the Bank of Avilla. He looked Mr. Russell in the eye, and then saw his.45 holstered while he sat behind the teller window.