The exterior shot for the hospital at which Paul Drake is in Room 328 is USC Medical Center, which also served (and still serves) as the exterior for the ABC soap opera General Hospital (1963). David Lewis, who played Mr. Lanphier, also starred as Edward Quartermaine on ... General Hospital.
One of the very few episodes in which no one is arrested or charged with criminal homicide before Perry exposes the murderer.
When Perry questions Caudere in French, he is saying, "Doctor, where did you study medicine? At the Sorbonne?"
One of a very few episodes involving a coroner's inquest rather than a criminal trial or hearing. In this case, Burger appears, but not to prosecute anyone (yet). He is there strictly as an observer, although he does get involved.
The exterior shot of Nappy's restaurant was actually the original Sunset Grill burger joint on Sunset Boulevard, made famous by Don Henley's 1985 song Sunset Grill. The structure was torn down in 1997 and replaced with a two-story restaurant also called Sunset Grill