Fingerprints in Detective Stories

The history of fingerprints in detective stories is a curious one; their use in detective stories almost never parallels their use in real life. Which is to say, fingerprints in detective stories are always something to be worked around, while in real life they are a tool for catching criminals.

Fingerprints have been known for a very long time, of course, but their use to identify criminals is comparatively recent. Like most things the history of the technology around fingerprints is a long one, but we can suitably take it up with a book by Sir Francis Galton, entitled Finger Prints, in which he a published detailed statistical analysis showing that finger prints were sufficiently unique that they could be used as identification. That is, if a finger print found somewhere matched a finger print taken from a person, you could be confident that it was, in fact, that person’s fingerprint.

Details are a little hazy to my very cursory reading on the subject, but shortly after Paul-Jean Coulier developed a method of transferring fingerprints from objects to paper using iodine fuming we see fingerprints start to be used to identify criminals by police forces in 1901, with the first conviction for murder based upon fingerprint evidence in 1902.

It is not long after this that we see fingerprints start to appear in detective stories; the first I can think of off of the top of my head in the Sherlock Holmes story The Adventure of the Norwood Builder. In it, a bloody thumb mark is found near where Mr. McFarlane would have gotten his hat before leaving. The thumb print was a false one, of course, made from a cast of a thumb mark left in sealing wax. This discovery has nothing to do with the fingerprint itself, however—the criminal had put it there overnight, and Holmes had observed that there was no mark in that place the day before, proving McFarlane’s innocence.

The next instance I’m aware of—I’m sure that there are others before it—is the first Dr. Thorndyke story, The Red Thumb Mark, published in 1907. Here we have another fingerprint, again in blood, but this time the case revolves almost entirely around the thumb print. It turns out to be a forgery, which Thorndyke proves by careful examination of the thumb print under high magnification. The denouement, for so it might be called, is entirely about the process for using photo-lithographic techniques for creating a stamper capable of creating duplicates of a fingerprint.

I would like to skip forward, now, to 1921, and The Strange Case of Mr. Challoner. This features the detective Malcolm Sage, and he delivers a very curious lecture on the use of photographs and fingerprints. I will quote it in full, because it’s worth reading for the historical curiosity:

“There is no witness so sure as the camera,” remarked Malcolm Sage as he gazed from one to the other of two photographs before him, one representing him holding an automatic pistol to his own head, and the other in which Sir James was posing as a murderer.

“It is strange that it should be so neglected at Scotland Yard,” he added.

Silent and absorbed when engaged upon a problem, Malcolm Sage resented speech as a sick man resents arrowroot. At other times he seemed to find pleasure in lengthy monologues, invariably of a professional nature.

“But we use it a lot, Mr. Sage,” protested Inspector Wensdale.

“For recording the features of criminals,” was the retort. “No, Wensdale, you are obsessed by the finger-print heresy, quite regardless of the fact that none but an amateur ever leaves such a thing behind him, and the amateur is never difficult to trace.”

He paused for a moment; but the inspector made no comment.

“The two greatest factors in the suppression of crime,” continued Malcolm Sage, “are photography and finger-prints. Both are in use at Scotland Yard; but each in place of the other. Finger-prints are regarded as clues, and photography is a means of identification, whereas finger-prints are of little use except to identify past offenders, and photography is the greatest aid to the actual tracing of the criminal.”

By the later 1920s, fingerprints, where they exist at all, are almost exclusively red herrings, and I think by the 1930s they more-or-less never show up. Consider this scene from Gaudy Night, in 1935.

“Is there no material evidence to be obtained from an examination of the documents themseves?” asked Miss Pyke. “Speaking for myself, I am quite ready to have my fingerprints taken or to undergo any other kind of precautionary measure that may be considered necessary.”

“I’m afraid,” said Harriet,” the evidence of finger-prints isn’t quite so easy a matter as we make it appear in books. I mean, we could take finger-prints, naturally, from the S.C.R. and, possibly, from the scouts—though they wouldn’t like it much. But I should doubt very much whether rough scribbling-paper like this would show distinguishable prints. And besides—”

“Besides,” said the Dean, “every malefactor nowadays knows enough about finger-prints to wear gloves.”

There’s also a later scene where Lord Peter dusts a door for fingerprints.

“Am I really going to see finger-prints discovered?” asked the Dean.

“Why, of course,” said Wimsey. “It won’t tell us anything, but it impresses the spectator and inspires confidence…”

He went on to dust for fingerprints right up to the top of the door, which he said was “merely a shopwindow display of thoroughness and efficiency. All a matter of routine, as the policeman says. Your college is kept very well dusted; I congratulate you.” In fact, he suspected the use of strings over a door to manipulate things inside, and was checking to see if there were marks; at this late juncture checking for fingerprints is merely cover for some other, more useful, activity.

As we move out of the golden age and into more contemporary detective fiction, we tend to find that fingerprints either implicate an innocent person in a meeting with the victim prior to his death or else turn out to belong to the victim in very strange places. In short, they turn out to be either red herrings or further puzzles. (Obviously, I am painting with a very large brush, here.)

Curiously, while there seems to have been a spate of forged fingerprints shortly after the things became used as evidence, I can’t recall seeing or reading of any forged fingerprints in stories written in the last 100 years. Most of the time, fingerprints are like cell phones in horror stories—something the author feels duty bound to add a line or two explaining away, but otherwise things one would just as soon forget.

There is a close analogy in DNA evidence, which to some degree are the fingerprints of our day. Any idiot can get a lab result saying that person A was in place B where the crime was committed, and he should never have been in place B, therefore he committed the crime. This requires not a detective but merely a well-trained monkey. It is, therefore, entirely uninteresting. Fingerprints at least have the advantage that the amateur can take fingerprints almost as well as the professional; DNA evidence simply cannot be found by the amateur. DNA evidence is, therefore, merely annoying, from the perspective of the mystery author. It can be used, as fingerprints were, to frame innocent people, but not really better than any other evidence. Hair is a great place to take DNA from, but matching hair to a person is an age-old thing; finding the innocent suspect’s hair at the scene of the crime can be done without DNA evidence.

I know in my own stories I occasionally feel obliged to explain why there is no DNA evidence, though I’m always annoyed by it. To be fair, I also used DNA evidence in one of my stories, though only as potential clinching evidence that would have been worthless without knowing who to test (the test would have happened after the book was over).

I suspect that DNA evidence will eventually go the way of fingerprints—something that needs only the most cursory explanation to wave away, since the reader is as uninterested in it as the author is.

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