Gunsmoke (1955)

S6E37 Melinda Miles

After Roy Tayloe is killed after a poker night, hot-headed Harry Miles is convinced that Tom Potter, Melinda's boyfriend, is the culprit. Frustrated with Matt's slow approach to solving the case, Miles grows increasingly agitated and threatens to take matters into his own hands by vowing to kill Potter if he doesn't keep his distance from Melinda.