Vic Morrow's character, Vince Shirer, did not use a gun to kill in this episode, he used a knife. During the run of Combat! (1962), in an interview Morrow revealed he didn't like guns.
This is the second of two appearances Vic Morrow makes in this series, appearing as a different character each time. His first appearance occurs in The Tommy Karpeles Story (1960) from season two. Within a year of appearing in this episode of The Untouchables (1959), he would star in his own series, which would run for five seasons: i.e. Combat! (1962).
This is the seventh of eight appearances Frank DeKova makes in the series. Except for the first season, when he appears as Louis Campagne three times, all his other appearances are in the roles of different sinister characters, roles he frequently played throughout his acting career. Even so, he is perhaps best known to audiences from the 1960s for his recurring role in a TV sitcom as Chief Wild Eagle from F Troop (1965).
This is the fifth of six appearances Joseph Ruskin makes in the series and first of two times that he appears in the role of gangster Lepke Buchalter.