CARS: No cars. From The Cars by Greg Cockerill.

Anomaly: Mary LaRoche, listed as Lisa (as in Lisa Kudrow) Hiller, is called Liza (as in Liza Minnelli) throughout the show. [D. A. Supernaw]

The book, Legal Medicine, Pathology and Toxicology, by Gonzales, Vance, Helpern and Umberger, that is discussed in court was indeed an authoritative textbook on the subject at the time. Helpern was a friend of ESG. Submitted by daveb, date unknown.
+ In an extensive forword, Gardner dedicated his book The Case Of The Hesitant Hostess (1953) to his friend, Dr. Milton Helpern (1902-1977), who for 20 years was New York City's Chief Medical Examiner. submitted by DyNama, 9/3/2014

Martha Vickers (who played Carmen Sternwood in the classic Bogart film The Big Sleep, who was one of Mickey Rooney's wives, and who died much too early at age 46) makes her only Perry Mason appearance in this episode. Submitted by PaulDrake33.

About halfway into the episode Paul reports that Buzzie was with a “weird-looking chick” named Sheila Hayes who drives a 1958 300 SLR that costs $13,000. That same Mercedes in nice shape would be over $400,000 today. Posted by Eric Cooper, 23 December 2009.

Why does ritzy Sheila Hayes hang around with Buzzie anyway? DOD 08/03/20

Sightings: Little Old Lady in a Hat appears (hazily) in the first courtroom scene on the defendant’s side. Another recurring “guest” is a distinguished woman with long hair and a hat (a.k.a Distinguished Lady #1). Submitted by gracenote, 8/19/2010.
+ Other spectators include “Miss Carmody” and Quiet Old Man #1 (who is seen in an unusual profile view during the exit from the courtroom). And that may be Distinguished Gentleman #1’s distinctive hairline behind the closeup of Sheila Hayes. Is it? Submitted by alan_sings, 16 Oct 2010.
+The Distinguished Lady #4 watches from both Burger's and Perry's side. Submitted by BigBill767, 2/4/17.

The man playing the coroner is one of the more prolific character actors from classic TV. Submitted by gracep, 19 August 2010.
+ That's Jon Lormer, especially familiar to Star Trek fans for his role in the show's pilot episode, "The Cage," and others. Submitted by francis, 7/11/14.
++ "The Cage" was the Unaired, 1st pilot (1965); Jon was uncredited, but he did appear in 2 credited roles in '67/'68. Mike Bedard 6.19.16
+++ Extensive footage from the pilot, "The Cage" was incorporated into the two-part episode "Menagerie" OLEF641 12/15/2020

The statuette that Sheila Hayes taps on Harry Jackson’s desk as she says “that” is of course a miniature reproduction of Auguste Rodin’s The Thinker. Submitted by gracenote, 4/11/2011.

When she calls to report the murder, the secretary gives the address as 1-1-7-2 Wilshire. Since LAPD has jurisdiction, this may put the office in the vicinity of Wilshire and Lucas Av in downtown Los Angeles...MikeM...6/20.2016

Uncredited Actors: Don Anderson is the bailiff guarding the prisoner Green as he speaks to his attorney Perry. Later he turns up in the courtroom, and then escorts the defendant out again. Submitted by gracenote, 4/11/2011.

This is the only PM writing credit for William Stuart...MikeM. 9/26/2016

Tom Drake is perhaps best known as 'the boy next door' in Meet Me In St. Louis opposite Judy Garland. One of my favorite of his roles was in the somewhat obscure 1959 western Warlock in which he plays a cold-blooded criminal. The movie stars Anthony Quinn and Henry Fonda; Trekkie alert: DeForest Kelley has a smallish but fairly pivotal role in Warlock. OLEF641; 10/17/2017.

This is the first of five PM appearances for veteran character actor Walter Burke (Freddie Green), whose parents were Irish immigrants living in Brooklyn. Beginning on the stage in New York, Burke transitioned to movies and then television. His last television roles were in 1980. Walter Burke passed in 1984 at the age of 75...MikeM. 7/6/2018

TCOT Substitute Coffee Cops: My gosh, in this episode, as we await the entrance of the Canonical Curious Coffee Cups, we get BOTH sets of Substitute Cups. First Danny and Freddie eat their bagels, schmear, and Nova Scotia lox on the conical art deco set with the painted rings and the 7-shaped handles. Then, in Perry's office, Perry, Della, and Paul sip and chat with the so-far-unidentified floral / aquatic set of restaurant ware. Submitted by catyron, December 31st, 2020.

TCOT Missing Blink: This is a small point, but hey, on this wiki we are detail oriented! In this episode, and others in similar high-powered office settings, the push buttons on the phones don't light up when they erupt into a ring. Too much work and wiring for the prop people I expect. Having stared down that sort of phone for years, for me it's a conspicuous absence. JohnK, 17 August 2021