The method of the murder is a point to be carefully chosen and this consideration of course includes the weapon.
Shooting is perhaps the means most often used, with stabbing as a close second. If a shooting, the weapon is usually a revolver, or occasionally a rifle. In this case, care must be taken that the scene is out of doors; or, if indoors, in an isolated apartment or so placed that the report shall be out of hearing of the other characters, unless immediate discovery is intended.
Various devices are used to keep the innocent characters from hearing the shooting. In one case only a half-charge of powder was put into a gun. In another, of recent date, a silent bullet was used.
A strong point is always made of the evidence of the weapon, if it be found. But, as we have before hinted, do not persist in having the revolver marked with the initials of a perfectly innocent person, for this has come to be looked upon as a tacit acquittal. It is hackneyed, also, to have the pistol one of a pair, and trace it by means of its duplicate still reposing in its case in the criminal's library. Learn to avoid these over-worked devices, as there are surely plenty of others. If a pistol is your chosen weapon, treat it either inconspicuously, or in some novel and original fashion that will interest the reader.
The advantage of a stabbing is principally that the weapon may be picked up at the moment, in a sudden impulse to kill; while a pistol usually implies a premeditated murder.
A weapon picked up on the spot has the advantage of not necessitating its concealment after use, for it incriminates no one in particular. Oftenest this weapon is a dagger used as a paper cutter, and so lying at hand on a table. Or a dagger or sword which is one of a decorative group on the wall of the room. Another weapon which has crept into use of late y ears is the hatpin. This, though popular among writers, is implausible and in many cases impossible; for the average hatpin bends but does not break. Yet one author after another kills his victim by stabbing him with a hatpin which breaks off and disappears in the wound.
One would-be clever author caused his victim to fall violently forward (with his mouth conveniently open), and allow a hatpin held by a near-by lady to strike through the roof of his mouth and pierce his brain. The obliging hatpin broke off at just the right place, and as the lady concealed the head end, the point end of the fatal weapon was never discovered. This related incident is practically impossible and should not have been used.
A Spanish story called "The Nail," by Pedro de Alargon, practically reverses this method. A large nail was driven into the victim's skull and accomplished its purpose immediately. The head of the nail was concealed by the man's thick hair, and all unsuspecting of villainy, three medical experts declared the man's death due to apoplexy. Nor were they entirely to blame, as the physical effects brought about by the nail were precisely the same as the conditions of death by apoplexy.
The nail is a horrible suggestion, but whatever weapon brings about violent death is necessarily horrible. It is wise to dwell on the physical details as little as possible. Granted a murder, there must be a method, and if the exigencies of the story demand a horrible method, so be it; but remember Poe's injunction, and when painting the decayed cheeses make them look as little like decayed cheeses as possible.
Poison is a method giving the author a wider scope and necessitating somewhat legs gruesome conditions. It is easier to administer poison than to shoot or stab. Poison may be given in food or drink, or introduced into medicine or administered in more ingenious and original ways.
If this method is used, the author should study up on poisons and their effects, and not run the risk of making absurd mistakes in his text. Abstruse scientific information is not necessary; enough can be learned from an encyclopaedia or a medical dictionary; but the plausibilities must be maintained.
A favorite poison with writers who know little of the subject, is "a curious Indian or Persian drug, which acts instantaneously and leaves no trace." This drug, with its various and unintelligible names, has been somewhat over-worked; but it is acceptable because of its mystery and it is useful because its description is so vague as to need no real knowledge of it on the part of the author.
The plot of a poison murder implies more complexities than a death by shooting or stabbing. The poisoner is a person of more ingenuity and is more anxious to escape discovery; and it also gives scope for treachery and deceit. Then, too, it has the advantage of allowing the detail of bloodshed to be omitted, thus making the scene less ghastly to sensitive minds.
Drowning and strangling and chloroforming eliminate also the necessity for bloodshed, and have the added advantage of requiring no especial weapon; though the presence of the weapon, or the absence of one known to have been used, is a valuable asset to the mystery writer.
Though the principal means of murder are enumerated above, the various manifestations of these means are innumerable.
The ambitious writer often strives to find some new and original way of committing a hackneyed crime. So far has this been carried, that the latest detective stories employ the use of cultures of typhoid or diphtheria to bring about the necessary demise.
Such means are perfectly legitimate in detective fiction, and if detailed with accurate and correct scientific knowledge are convincing, though not picturesque. Sherlock Holmes, with his fancy for the bizarre, rarely is satisfied with a plain shooting or stabbing. He uses such means as a blunt weapon, pushing into the water, a venomous snake, a harpoon, a poker, charcoal fumes, and a fall from a steep precipice.
One of Anna Katharine Green's best stories, "Hand and Ring," employs the homely weapon of a billet of fire-wood. We are told at the outset that:
Half the criminals are caught because they do make tracks and then resort to such extraordinary means to cover them up. The true secret of success in this line lies in striking your blow with a weapon picked up on the spot, and in choosing for the scene of your tragedy a thoroughfare where, in the natural course of events, other men will come and go and unconsciously tread out your traces, provided you have made any. This dissipates suspicion, or starts it in so many directions that justice is at once confused, if not ultimately baffled.
This is a sound principle of construction, and is the starting point of many of the best detective stories.
In "The Mystery of the Yellow Room," the author goes back to the primitive weapon of a mutton bone, and in the skillful hands of both author and criminal this weapon is truly dramatic.
An author's first plot almost invariably centers around a shooting or a stabbing affair. It is in his later efforts that he feels moved to vary his methods.
Regarding crimes other than murder, we find that more depends on the setting. A robbery, however great the booty, must be made interesting by unusual characters or conditions, and must implicate the hero or other important characters to the danger point. The discovery of the wrong-doer must mean disgrace and disaster of the strongest sort. For your detective story fancier is an extremist; and, owing to the predominance of murder stories and capital punishment, a short imprisonment for a robbery seems tame by contrast.
"The Moonstone" is a robbery story, but it combines all the elements that make for a dramatic setting, and though not the main motive, it includes a murder, and also a suicide, incidentally in the plot. It is one of the very few full-sized novels built upon a robbery, and it required the peculiar genius of a Wilkie Collins to hold the reader's attention through its five hundred pages.
Other crimes than those we have considered, such as forgery, arson, blackmail, etc., are used only by authors in search of a novelty. They fancy that these crimes will interest because they are not so hackneyed as murder and robbery. But unless worked up with great care as to atmosphere and technique, stories of these crimes often prove dull reading.
Some authors incline to such subjects as Nihilism and the workings of secret societies. These are not of such general interest as the ones we have been discussing, but they offer picturesque possibilities and scope for melodrama.