Handsome Hubert, one of the wrestlers Ellery and Inspector Queen are watching when Velie tells them about the murder, is based on Gorgeous George, a flamboyant professional wrestler from the 1940s and 50s. Ironically, his last match before retirement was against a masked wrestler, as Hubert's match in this episode is.
When Ellery and Inspector Queen arrive at the murder scene, a police car can be seen bearing the marking "115th Precinct". This would put the Kendrick home in Jackson Heights, in north-central Queens County.
The piece that Simon plays on Stephanie Kendrick's piano is Franz Liszt's third and final "Liebestraum".
At 1:52 the camera focuses on a hardcover book. Its title and author? "The Adventure of Lover's Leap" by Ellery Queen.