This is the only appearance on Perry Mason for the Mexican-American actress Margo. This would also be her last appearance in either TV or movies. While Margo appeared as Maria in the 1937 classic film Lost Horizon, she is best known as the wife of Eddie Albert for 40 years, and the mother of Eddie Albert, Jr. Submitted by PaulDrake 33, 18 August 2009.

The is the only appearance on PM by Rudy Solari (1934-1991). He later appeared on the Star Trek episode "The Paradise Syndrome". Fans of both may notice that he shows no humour, and smiles not once in either episode. Submitted by Chief Kurtz, 10 January 2022

Star Trek Alert: In addition to Rudy Solari mentioned above, two other actors in this episode will appear in the Star Trek universe. Anthony Caruso, who was cast in three Perry episodes, portrayed the alien mobster Bela Okmyx in the original series Star Trek episode "A Piece of the Action." Paul Comi, who makes his only Perry appearance here, was in the original series Star Trek episode, "Balance of Terror," along with fellow Perry alum Robert Francis Chadwick (TCOT Fatal Fetish). Submitted by MyFavoritePolarBear, 11/23/22.

Music:The tune that Paulo Porro (Fabrizio Mioni) hums in the opening scene (and whistles in a later scene) is “La Donna É Mobile,” from the opera Rigoletto by Verdi. Submitted by gracenote, 4/26/2011.
+ In the Italian restaurant, when Perry dines with the priest, an instrumental version of the famous Neapolitan song "Santa Lucia" plays in the background. This song was popularized by the Neapolitan operatic tenor Enrico Caruso, and we have, in this episode, a Mr. Caruso portraying a character named Enrico, plus a stray reference to Naples at the close of the show.. Submitted by catyron, July 7th, 2018
+ And when Perry and the priest return to the restaurant with Paulo from the police station, "Santa Lucia" is again playing, as if on a loop. Submitted by Chief Kurtz 10 January 2022

Sightings: The Pencil Mustache Man who resembles Leo Carrillo turns up in the courtroom gallery as the people file in. Distinguished Gentleman #1 is the court reporter. Submitted by gracenote, 4/26/2011.

Character Names: Although not listed in the credits, Giangiacomo’s last name is a Bacio, too. Submitted by gracenote, 4/26/2011.
+This was another story where a few characters were not given a first and last name: Serafina, Mr. Dodson and Uncle Fiastri. Added by H. Mason 4/26/15

San Francisco: For at least the fourth time Paul Drake went to San Francisco to get information for a Perry Mason murder case (#73, 96 and 223 [went with Perry]). In episode 189, TCOT Floating Stones, the murder and court proceedings were in San Francisco. Submitted by H. Mason 4/26/15

This is the only PM appearance for Linda Marsh, who also made a single appearance on "Ironside"...MikeM. 2/21/2017

This is the last of eight PM writing credits for Milton Krims. According to IMDb, this is the final television writing credit for Krims. Per IMDb, Milton Krims last screenplay credit was in 1963, a joint US-Italian movie filmed in Italy...MikeM. 2/27/2018

This is the only PM appearance for Nico Minardos (Giangiacomo), who was born in Athens, Greece. Minardos would later appear in two episodes of "Ironside". Nico Minardos passed in 2011 at the age of 81...MikeM. 7/3/2018