Jenny compares herself to Torchy Blane, a character in a series of movie mysteries in the late 1930s.
This is the only episode where Ellery wears a tan hat instead of his tweed ones.
When you see the Gotham Book Store it is a nod to the Gotham Book Mart in NYC. Also, the book mark in the book see in the book store.
At 43:39 when Rosh Kalee asks to speak in private with the Queens to reveal his secret identity, they move just a few feet away from the suspects. Staying in the same room and not lowering their voices, they could easily have been overheard.
At 44:53 Ellery displays a photo which he states is "the Russian ship Larissa". The photo clearly has the name LARISSA on its bow. A Russian ship would display its name in the Cyrrilic alphabet used in Russia, not the English alphabet.