"I've been a fool about this. Locked rooms, as you said, on the brain."- Detective-Inspector Humbleby (Edmund Crispin's "The Name on the Window," collected in Beware of the Trains, 1953)
Georgette Heyer was a British novelist well-versed in several genres, consisting mainly of Regency romances, historical fiction and mystery novels, which were largely republished over the past fifteen years – including the books chronicling the cases of Superintendent Hannasyde and Inspector Hemingway.
Reportedly, Heyer garnered most of her literary fame in the field of historical romance novels. She wrote many novels that were set in the Regency period or the Georgian era, which made Heyer "legendary for her research" and "historical accuracy," but her mystery novels seem to have failed to scale the reputational heights of her historical fiction.
However, I've read some interesting, if varying, opinions from my fellow and highly respected connoisseurs in murder about her work.
The opinions seem to be divided where some of her most recognizable mystery novels are concerned, such as Why Shoot a Butler? (1933), Death in the Stocks (1935) and The Blunt Instrument (1938), but are overall consistent and positive about Envious Casca (1941), which is a conventional country-house mystery in the spirit of Hercule Poirot's Christmas (1938) by Agatha Christie – and even has a locked room mystery at the heart of its plot. So, guess which Heyer mystery this predictable hack picked?
Envious Casca takes place at the manor house of a wealthy curmudgeon, Nathaniel Herriard, where his much more cheerful brother, Joseph, has taken charge of preparing a Christmas party and invited a small band of people. Unfortunately, it's a collection of highly incompatible personalities, which leads to irritation and murder!
There are, first of all, the Herriard brothers: Nathaniel is a rich, semi-retired businessman who became somewhat of an old humbug, who believed Christmas to be "a series of quarrels between inimical persons bound to one another only be the accident of relationship" and "thrown together by a worn-out convention which degreed that at Christmas families should forgather" – which is simply begging to have several spirits haunting up your bedroom a day before Christmas. Joseph is a much more pleasantly person, overly nice even, who spend most of years as a traveling actor and has since two years returned, but is financially completely depended upon his brother. Joseph brought along his wife, named Maud, who spend most of the story irritating the people around her by sharing tidbits of information from the biography she's reading about an Austrian-Hungarian empress.
A dead brother of Nathaniel and Joseph left two children behind: a "rough-tongued young man with no manners," named Stephan, who's the prospected heir of Nathaniel's fortune and a sister, Paula, who equals her brother in all his unpleasant characteristics.
Stephen has brought along Valerie Dean: his pretty, but childishly naïve, finance whose personal motives makes her a common gold-digger in the eyes of Nathaniel. Paula is a stage-actress and is accompanied by Willoughby Roydon, a postmodern playwright of "grimly realistic plays," which is why Nathaniel refuses to cough up several thousands of pounds to finance his play – much to the chagrin of Paula who wanted the main part in the play. The party is rounded out by Mathilda Clare, a cousin, and Nathaniel business partner, Edgar Mottisfont.
In such company, you can almost understand why an old grouch like Nathaniel refuses to answer the knocks on his bedroom door. As Inspector Hemingway remarked, he would in his place have locked himself in his room and "very likely shove a heavy piece of furniture" against the door, but there was a far more serious reason why no answer emanated from behind the locked bedroom door. A murderer had poked Nathaniel in the back with a knife and "then dematerialized himself like the spooks you read about."
The locked room aspect of the murder has Inspector Hemingway and Sergeant Ware pleasantly baffled, which leads to minor, but interesting, discussion how the murder could've escaped from the room – which includes "the old pencil-and-string trick" and the possibility that "the key was turned with a pair of eyebrow-pluckers."
Something of historical interest about the tool consisting of "a pair of forceps shaped a bit like eyebrow-pluckers to open locked doors," because it’s a burglary-tool called an "oustiti." I was unable to find a picture of those forceps, but I came across a reference describing it as "an essential item of a burglar’s tool kit" and it even quoted this book! The tool was also mentioned in Modern Police Work (1939), which you can find and read here.
Anyhow, the eventual explanation for the locked room is as simple as it's risky and the only weakness is the luck of the murderer that everything panned out the way it did, but loved how the solution took its cue from history – instead of being pulled from the burglar's tool kit. I also appreciated how the murderer and Hemingway basically stumbled to the idea for the locked room trick by discovering the same thing, which was the only part of the puzzle that had baffled Hemingway up to the near end. However, it's not a classic of the impossible crime genre. But it was nice enough.
Hemingway saw through the murderer's ruse and hardly believed anything that was thrown at his way, which included a cigarette case, a missing book, a bloodstained handkerchief, some rude behavior and even a link to the Sino-Japanese War. The good inspector knew how to separate the clues from the red herrings and did not belong to the "lot of half-baked people" that murderer banked on believing an apparent innocent person to be actually innocent. Only problem is that most of readers probably belong to the same category as Hemingway. I read a very apt comment how Heyer here obviously tried to out-Christie Christie in the least-likely-suspect department, which made the murderer stand-out more and more with each passing chapter – making the revelation of this person’s identity a couple of chapters before the ending a good move.
Regardless of these minor trivialities, I genuinely enjoyed Envious Casca as a whole. It's an extremely conventional mystery novel with a conservative plot-and cast of characters, which can hardly be labeled original, but the story moves around gracefully within the confines of the conventional manor house mystery. Like a swan elegantly paddling around in a fountain.