This episode is based on the Erle Stanley Gardner novel of the same name, which would also serve as the basis for the final season episode, “The Case of the Impetuous Imp”.

The $50 Dorian gets for the “note” would be about $368.28 in 2007 dollars. The “missing” $10,000 would be around $73,656.13 today—enough to be a downpayment for Las Chalupas. Submitted by billp, 12/27/2008.

Stuck in a rut?: Second episode in a row featuring boats. Third episode in a row featuring an affluent, childless, unhappily-married couple. Submitted by 65tosspowertrap, 3/22/2014.

The geography of Perry’s office changes through the years. The library in this episode would later be a bathroom; in most other episodes, the library is to the right of that large bust. DOD 06/01/20

French connection? When Perry and Paul visit the Mexican restaurant to question Nina Santos, she sits with them at a table, calls the waitress over and, in Spanish, orders coffee and tostadas for the gentlemen. The waitress jots down the order and responds "Oui"! Submitted by francis, 5/26/14.
+ It sure is hard to tell if she said "Oui" or "Si". Added by H. Mason 9/30/14''
++I listened several times. I heard "Oui."...MikeM. 7/25/2016
++ I think it was not "oui" but "muy", as in "muy bien". I think the last word didn't get picked up. Added by Crunchy 10/16/2019
+++ The whole thing with Paul trying to cool off the hot Mexican sauce with water isn't how you do it, milk and/or sour cream is the ticket. Submitted by HamBurger, 8/6/2017
++++ This is odd. My memory from when I saw the show in 1957 is that Paul didn't drink from the water jug, but rather from a flower vase, because I recall him grabbing the flowers and throwing them down on the table before drinking. Clothears 1st Oct 2019.

During that interview, when Perry asks Nina if Agatha had a large sum of money on the boat, she claims not to know. Questioned by Burger, she freely admits knowing Agatha had $10,000. with her that night. DOD 06/01/20

For someone who swam several yards in her clothes and then spent the night in her car, Sally looks surprisingly well groomed when she goes to Perry's office - and that note stayed surprisingly legible. ( and it is definitely "oui").

Bad Accent Dept.: Although her actual Spanish is perfect, when Señorita Santos speaks English with a (presumably) Mexican accent, she is much less convincing. This may be because the actress's original name was Nadja Vonkorytniuk. Submitted by francis, 5/27/14.