The Texan Season 1 Episode 3 The Troubled Town

Hot-headed Johnny Kaler, embarrassed that he's been caught cheating at cards, provokes Bill Longley into a barroom brawl and is quickly thrashed. Later in the evening Johnny tries to kill Bill, but dies when an unknown assailant shoots him in the back from the shadows. Johnny's big brother Mike still blames Longley for the shooting and calls him out for a showdown.