Herbert "the Cat" Nobel. Nobel was a bodyguard for Sam Murray, who paid more protection money, and became the top dog in Dallas. Binion and Ivy Miller caught Murray without his bodyguards, and Miller shot Murray. Binion was again in control until a 1946 Cleanup, and decided the desert climate was more to his liking.
I found this information in "Gamblers & Gangsters" by Ann Arnold, about Fort Worth's Hell's Half Acre in the 40's-50's