In "A Murder of Necessity," a man kills his blackmailer but then realizes that there is a witness to his crime.
Afterwards, he realizes that Herbie had been in the middle of a phone call. The phone was off the hook, and somewhere out there, a stranger heard what he did.
Mark decides to try to find out who was on the other end of that call by going through the list of people that Herbie was in contact with that day. As he does, Mark realizes that he may have done them all a favor by killing Herbie.
"A Murder of Necessity" was written by Richard Pedicini and produced/directed by Elliott Lewis. Robert Young starred. Also appearing were Joseph Kearns, Charlotte Lawrence, Joe Gilbert , Howard McNear, Lou Merrill, and Paula Winslowe. This episode aired on March 24, 1952.
(Image from Stock.xchng)