In the re-enactment of the TV newscast the newsreader refers to television as "your window on the globe." However, this phrase was not heard on the original broadcast.
When Monica leaves her dying clue, the outlet she pulls the TV plug out of is three-holed, meaning that it's a grounded plug. Such outlets didn't become standard until 1962.
Ellery picks up Monica's framed photo when he examines the murder scene. However, when he puts it down it transforms into a photo of a different woman, wearing a pale blouse and seated on a visible chair.
When Simon Brimmer does his radio broadcast about Monica Gray's former lovers, Ellery becomes agitated. His father knew about the men, but did not mention them to Ellery, as none of them could have been guilty. Ellery starts searching for a piece of paper, and exclaims, "Why didn't I really read those files?" The only files we've seen were six months worth of local robberies, and Ellery did, in fact, read them and discover the connecting factor in them. Robbery files would have had no information about Monica's lovers.
Trivia: Since the pilot took place in 1947 (the title card read "New York City 1947") and this episode took place on New Year's Eve 1946, the events of this episode takes place before the events in the pilot.
Ellery refers to his galpal as "Jenny" instead of "Kitty" when he first knocks on her apartment door.
At the end of the episode, when the murderer confesses, Tilda is shown putting her left hand up to her face. The camera shifts to Ellery for a brief moment, then back to a long view of the study. Tilda suddenly is holding her right hand to her face.
Frank Flannigan boasts to Inspector Queen that his column is right on the front page of the newspaper--but we had just clearly seen that it was on the third page.
Frank Flannigan's column is presented as a series of brief bits of information. The first bit starts off sensibly enough, but in the second line the grammar suddenly skews, and the confusion goes on from there. The second bit is properly written, telling of a taunting letter written by L.A's "Butterfly Killer" to the local police. The third line seems to be political doublespeak that (naturally) makes little sense. The fourth bit is the focus point about Inspector Queen keeping his "family" secrets. The fifth, (and the last visible) bit is taken word for word from the article printed to the right of the column.
When Pearson offers Dobrenskov asylum, he says that he wants Dobrenskov to tell them all about a man named Abel. If Pearson was referring to the Russian spy who would be captured and later exchanged for U2 pilot Francis Gary Powers, he was not arrested until 1957.
Trivia: It's revealed that Sgt. Velie once played Captain Hook in a high school play.
While Ellery and Simon are interrogating Bud, a waiter comes down the stairs and enters the room. The next shot shows the waiter repeating this movement.
Oddly, the well-known character actor Robert Cornthwaite is uncredited in the brief but important role of the mysterious Mr. Osterwald.
Goof: At the end of the episode, when Ellery gathers the suspects, he addresses the observing O'Neill as "Maddie" or "Mattie". In the credits, he is listed as "Knucks" O'Neill.
During the time that the police and Flannigan were cooperating to keep Dottie Lomax's death a secret, Ellery visited Lin Hagen's wife and his friend Terry. While speaking with them, Ellery directly mentioned the fact that Dottie had been killed, not simply wounded.
In the beginning Celeste was referred to as Lillian's cousin but when Ellery confronted her in the end he said that she's Clint's couin.
Trivia: Stan Buffo, named as one of the suspects in the opening, didn't appear in the reveal.