Joe Devlin is a renowned Irish poet, author, and raconteur. He, along with his own family and the heads of O'Connell Industries, is secretly a fundraiser and gun-runner for the Irish Republican Army. He raises money in Los Angeles for his radical cause through a charity ostensibly meant to help victims of terrorism. Devlin has a strong belief in honor. Thus, when Vincent Pauley, an arms dealer selling guns to Devlin, tries to skim off $50,000 for himself, Devlin shoots and kills Pauley for being a traitor. With Columbo hot on his trail, Devlin now in possession of the guns must arrange for their shipment out of the country. Final clue/twist: Columbo discovers that a bottle of whiskey at the crime scene has the same glass markings that Devlin habitually makes when he drinks from a bottle. Because every diamond has a unique cutting habit, Devlin's ring, which he uses to mark his bottles, is proof of his presence at the crime scene. Devlin accepts that Columbo has caught him, and is only disturbed when at the last minute Columbo foils his gun-smuggling scheme (Columbo had realized the guns were not yet on a ship going out to Southampton, but were on a tugboat escorting the ship to sea; Columbo saw the tugboat had the colors of the O'Connell shipping line). This was the last episode of the Columbo series broadcast on the NBC television network. Columbo's last line is "This far, and no farther", words spoken by Devlin as he marked a whiskey bottle to determine how much he would drink in a session. These words were taken from a speech by the Irish Parliamentary Party (IPP) leader Charles Stuart Parnell, a 19th-century Irish politician and supporter of Home Rule. A noted IPP politician of the same name as the fictional killer in this episode, Joseph Devlin, represented West Belfast early in the 20th century and opposed the use of violence in the cause of nationalist politics. Directed by: Leo Penn. Story by: Pat Robison, Howard Berk.