Sherlock Holmes's "Parthian shot" in Arthur Conan Doyle's "A Study in Scarlet" (1887)

In Arthur Conan Doyle's "A Study in Scarlet" (1887), just before Sherlock Holmes leaves the scene of the story's first murder, he tells Inspectors Gregson and Lestrade "one other thing" (that "Rache", painted in blood on the wall, is the German word for "revenge"). So Holmes, like Mr. Bucket in Dicken's "Bleak House", anticipates Columbo's later use of the same tactic. But then Dr John Watson characterizes Holmes's remark as a "Parthian shot". This cavalry tactic made famous by the Parthians of ancient Iran involves the considerable skill of riding forward while using a bow to fire arrows backward; the phrase is also the source of our expression "a parting shot". (Andrew Shields, #111words, 2 October 2022)