Blue Line

Investigations 101: The case of “The Red-Headed League” by Sir Arthur Conan Doyle – Instruction for modern-day detectives

September 15, 2023  By Gilles Renaud

The short story of The case of “The Red-Headed League” was published in 1891 and is found in The Adventures of Sherlock Homes. By reason of the early and lasting reception by the public of this great fictional character, and the reputation this fictional detective gained, Sherlock Holmes remains synonymous with excellence, indeed near perfection, in detective work.

Until the advent of CSI-type entertainment and the fascination with modern forensic evidence, his readers shared the belief that all investigators carried a “magnifying glass” and relied upon extraordinary powers of observation. More than another quality, Sherlock Holmes typified the ideal that a solution to a crime required information and that conclusions were quite premature and highly doubtful until all data had been mined and analyzed. In the ultimate analysis, science and not intuition, was the foundation for success in police work.

The best illustration of this philosophy of investigation is seen in the short story, “A Scandal in Bohemia”, also found in the collection titled The Adventures of Sherlock Homes, in Part I. The relevant passage follows, quoting his confidant and best friend, Dr. Watson, who asked Holmes:

“This is indeed a mystery,” I remarked. “What do you imagine that it means?” “I have no data yet. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.”


My objective in analyzing this short story is to provide guidance to police officers and especially detectives working in 2023. The instruction drawn from Sir Arthur’s imagination, serves to illustrate current elements of controversy in detective work and to offer insights into controversies touching upon demeanour evidence, interviewing witnesses and suspects, the exercise of judgment including understanding human nature, and the signal need for professionalism in this vital aspect of the protection of the community.

A first theme: Why pay attention to a piece of fiction from 1891?

My personal belief is that investigators succeed by asking sound and searching questions. The first might be: why read a short story from so long ago to become a better police officer today? In response, I quote from the late Dean John Wigmore, a leading law professor and writer on evidence: “The lawyer must know human nature. He [or she] must deal understandingly with its types and motives. These he cannot all find close around… For this learning he [or she] must go to fiction which is the gallery of life’s portraits.”1 If this proposition is sound, and surely it is, then detectives are in the same situation as lawyers, for they also must understand humanity, flawed and at times violent and or scheming. To achieve this goal, I propose that police officers turn to fiction.2

Demeanour evidence and investigative work

Assessing the body language of potential witnesses you interview

This introductory paragraph seeks to make plain a vital element of demeanour that the investigator must assess to further the aims of justice: non-verbal language that purports to communicate information may well contradict what the speaker has stated. It will assist the reader if I divert from this study of this short story in The Adventures of Sherlock Holmes to quote from William Shakespeare, as this immortal playwright contributed greatly to the belief that demeanour is both informative and misleading in informing our daily decisions.3

Perhaps the best known of these examples is found in Act 1, scene iv, l. 12 of Macbeth: “Duncan: There’s no art To find the mind’s construction in the face…” The companion reference that is best suited to underscore this point is set down in Act 1, scene vii, l. 82: “Macbeth … Away, and mock the time with fairest show: False face must hide what the false heart doth know.” I note as well how apposite is the passage that follows on the issue whether witnesses may be adept at feigning emotions: “… Let’s not consort with them: To show an unfelt sorrow is an office Which the false man does easy…” Refer to Act 2, scene iii, l. 135 of the same play.

A rather celebrated expression of demeanour evidence is found in Julius Caesar, Act 1, scene ii, l. 192: “Caesar. Let me have men about me that are fat; Sleek-headed men and such as sleep o’ nights: Yond Cassius has a lean and hungry look; He thinks too much: such men are dangerous.”

For investigators, the ultimate question is whether the attitude and manner of a witness reveals anything tangible, anything objective, upon which to conclude as to correct facts? Stated otherwise, what story did this tell, and was the story credible and reliable, especially considering the suggestions by Shakespeare that one can assume a favourable demeanour as well as hide a tell-tale one to avoid detection of one’s recent crime?

I think it useful at this stage to set out a few key passages from the case law to further the investigator’s understanding of this controversial subject, taken from R v Batchelor, [2022] OJ No 560 (Sup. Ct.), a well-reasoned judgment of Roger J.

50 Caution is required in considering favourable or unfavourable demeanour evidence. As indicated in R. v. M.M., 2016 ONSC 5027, at para. 59, and R. v. D.M., 2016 ONSC 7224, at para. 23, whether demeanour is related to in-court or out-of-court behaviour, it can be easily misinterpreted. As noted in R. v. Levert (2001), 159 C.C.C. (3d) 71 (Ont. C.A.), at para. 27, demeanour evidence has been known to play a role in wrongful convictions. Indeed, demeanour evidence alone can be a notoriously unreliable predictor of the accuracy of the evidence given by a witness as “the law does not clothe the trial judge with divine insight into the hearts and minds of the witnesses” and demeanour should not be sufficient where there are significant inconsistencies and conflicting evidence: R. v. Norman (1993), 16 O.R. (3d) 295 (C.A.), at p. 314, citing Faryna v. Chorny, [1952] 2 D.L.R. 354 (B.C. C.A), at p. 357.

51 More valuable means of assessing witnesses are to consider the consistency of what they have said on a material matter (internal and external contradictions) and improbabilities (exaggerations or illogical propositions). However, inconsistencies vary in their nature and importance; some are minor or concern peripheral subjects, others are more important or involve a material issue or something material.

52 Demeanour evidence is however not completely irrelevant; for example, the way that a witness testifies, such as unanswered questions, hesitations, challenging counsel, or run-on and unresponsive answers, may in certain circumstances be prudently considered by judges in their assessment of witnesses in conjunction with their assessment of all the evidence: see e.g., Hull, at paras. 8-9; R. v. Boyce, 2005 CarswellOnt 4970 (C.A.), at para. 3. Regardless, trial judges should not unduly rely on demeanour to make credibility findings, and any reliance on demeanour must be approached cautiously because looks can be deceiving. Importantly, a witness’ demeanour cannot become the exclusive determinant of his or her credibility or of the reliability of his or her evidence: see R. v. Hemsworth, 2016 ONCA 85, 334 C.C.C. (3d) 534, at paras. 44-45. Indeed, it is often difficult to accurately understand why a witness, whom the judge has never met before, exhibits certain behaviours: see R. v. N.S., 2012 SCC 72, [2012] 3 S.C.R. 726, at paras. 99, 101. Demeanour is therefore often of limited value because it can be affected by many factors, including the background of the witness, stereotypical attitudes, and the artificiality of, and pressure associated with, a courtroom or virtual courtroom. A perceived positive demeanour can equally be difficult to assess.

An excellent summary of the perspective of a trial judge is found in the wise words of Chief Justice Bowman in Faulkner v. M.N.R., 2006 TCC 239:

13 Where questions of credibility are concerned, I think it is important that judges not be too quick on the draw. […]

14 […] Since it is part of our job to make findings of credibility, we should at least approach the task with a measure of humility and recognition of our own fallibility. I know that appellate courts state that they should show deference to findings of fact by trial judges because they have had the opportunity to observe the demeanour of the witness in the box. Well, I have seen some accomplished liars who will look you straight in the eye and come out with the most blatant falsehoods in a confident, forthright and frank way, whereas there are honest witnesses who will avoid eye contact, stammer, hesitate, contradict themselves and end up with their evidence in a complete shambles. Yet some judges seem to believe that they can instantly distinguish truth from falsehood and rap out a judgment from the bench based on credibility. The simple fact of the matter is that judges, faced with conflicting testimony, probably have no better than a 50/50 chance of getting it right and probably less than that when their finding is based on no more than a visceral reaction to a witness. […]

In essence, the investigator must judge the demeanour of those they interview. To assist in this judging exercise, I now set out examples of demeanour drawn from “The Red-Headed League”. I think this exercise should fairly lead you to be guarded about your ability to judge the value of the body language you note, and to be quite guarded in thinking that any “positive” demeanour supports to any measurable degree the information you receive.

Classic examples of “body language” – A glance, that is questioning

“The stout gentleman half rose from his chair and gave a bob of greeting, with a quick little questioning glance from his small fat-encircled eyes.” I challenge you to be able to record accurately that a glance, obviously a rapid action which is described redundantly as “quick”, without a clear photographic record. And even then…

Classic examples of “body language” – Examine the face of the witness in the police station or at the scene

The first example references a “rueful” face. Thus, “Sherlock Holmes and I surveyed this curt announcement and the rueful face behind it, until the comical side of the affair so completely overtopped every other consideration that we both burst out into a roar of laughter.” Can one really draw any valuable conclusions from a so-called “rueful” face?

Classic examples of “body language” – Examine the eyes of the witness in the police station or at the scene

The first example from “The Red-Headed League” follows: “Sherlock Holmes stopped in front of it with his head on one side and looked it all over, with his eyes shining brightly between puckered lids…” After this first reference to “shining eyes”, consider “Sherlock Holmes stopped in front of it with his head on one side and looked it all over, with his eyes shining brightly between puckered lids…” Could it be that his eyes are always so, not unlike the many songs involving “bright eyes” and the character of Charlton Heston in “Planet of the Apes”?

I note as well “All the afternoon he sat in the stalls wrapped in the most perfect happiness, gently waving his long, thin fingers in time to the music, while his gently smiling face and his languid, dreamy eyes were as unlike those of Holmes the sleuth-hound, Holmes the relentless, keen-witted, ready-handed criminal agent, as it was possible to conceive…”

The nest reference to the facial area embraces the whole head, said to have demonstrated a “flush”. “I cannot see that there is anything very funny,” cried our client, flushing up to the roots of his flaming head. “If you can do nothing better than laugh at me, I can go elsewhere.” Again, I question what we can make of these observations.

Classic examples of “body language” – Examine the face of the witness in the police station or at the scene

I begin by referring to this passage:

“… Are you a married man, Mr. Wilson? Have you a family?’

“I answered that I had not.”

“His face fell immediately…” [After further information provided …] “My face lengthened at this, Mr. Holmes …”

I suggest that most readers will readily visualize what the author meant by penning these words, but the real question for police officers is what this communicates in fact: was he disappointed that his interlocutor was not married? How would this matter?

I now draw attention to this passage: “… the other was a long, thin, sad-faced man, with a very shiny hat and oppressively respectable frock-coat.” We read that he missed hos Saturday night card game for the first time in 27 years. Might this account for the sad face? Lastly, I note: “The solemn Mr. Merryweather perched himself upon a crate, with a very injured expression upon his face…”

Classic examples of “body language” – Examine the shoulder movements of the witness in the police station or at the scene

“‘And you are a benefactor of the race’, said I. He shrugged his shoulders. ‘Well, perhaps, after all, it is of some little use’, he remarked. ‘L’homme c’est rien—l’œuvre c’est tout,’ as Gustave Flaubert wrote to George Sand.”

Interpretation by one who knows the person whose actions are described

“‘Try the settee,’ said Holmes, relapsing into his armchair and putting his fingertips together, as was his custom when in judicial moods.” The problem you face is that you are not Dr. Watson, his boon companion who knows him well and is very familiar with his habits – how do you, a stranger, reach a sound conclusion based on a single interview? Consider this further example: “… Holmes chuckled and wriggled in his chair, as was his habit when in high spirits.” How do you get to know his habits to any reliable extent?


“‘That is better’, said John Clay serenely. He made a sweeping bow to the three of us and walked quietly off in the custody of the detective.” I tend to the belief that the extremes of emotion that may be read on the face of a witness may be objectively reliable, such as serenity on the one hand and what one reads in Edgar Allen Poe’s novella, The Narrative of Arthur Gordon Pym, of Nantucket, on the other. I refer to chapter 12 in which Pym and others, without food and water on a ship in the middle of the ocean, agree to a Dudley v. Stephens pact [(1884) 14 QBD 273] that one be killed to sustain the others. The words that follow describe the easy demeanour assessment respecting the features of the unfortunate one who drew the short straw:

… Presently one of the two lots was quickly drawn from my hand. The decision was then over, yet I knew not whether it was for me or against me. No one spoke, and still I dared not satisfy myself by looking at the splinter I held. Peters at length took me by the hand, and I forced myself to look up, when I immediately saw by the countenance of Parker that I was safe, and that he it was who had been doomed to suffer…

Human nature and investigative work – be wary of how people think and act

Embellish when recounting

“I know, my dear Watson, that you share my love of all that is bizarre and outside the conventions and humdrum routine of everyday life. You have shown your relish for it by the enthusiasm which has prompted you to chronicle, and, if you will excuse my saying so, somewhat to embellish so many of my own little adventures.” Can one be trusted to avoid adding a little mustard to whatever is being described when one knows that one has the attention of others? I suggest that the investigator must be careful in evaluating such “accounts” of the work of others.

Generous yet crooked

“… His brain is as cunning as his fingers, and though we meet signs of him at every turn, we never know where to find the man himself. He’ll crack a crib in Scotland one week [in the sense of a break and enter], and be raising money to build an orphanage in Cornwall the next…” This kind of dual nature in our capacity for good and “not so good” is often encountered in the cases tried before the criminal courts.

Identification – commonplace features

‘“As a rule,’ said Holmes, ‘the more bizarre a thing is the less mysterious it proves to be. It is your commonplace, featureless crimes which are really puzzling, just as a commonplace face is the most difficult to identify…’” I suggest that the tried and tested rule of great caution in cases of identification evidence suggests that an investigator will find it more difficult to assign great weight to an identification involving little or no peculiar features in the case of two strangers.


“The portly client puffed out his chest with an appearance of some little pride and pulled a dirty and wrinkled newspaper from the inside pocket of his greatcoat.” Again, care I required for we all know the adage “Pride cometh before the fall!” inspired by the phrase “Pride goes before destruction, a haughty spirit before a fall…” (Proverbs 16:18 New International Version).

Interviewing witnesses – lessons for the investigator

People might not be truthful

Investigators must always be mindful of the view that Shakespeare had Falstaff communicate to his wide audience in Act 5, sc. iv, l. 179 of King Henry IV (Part 1): “… Lord, how this world is given to lying!” A few lines later, Prince Henry states: “For my part, if a lie may do thee grace, I’ll gild it with the happiest terms I have …” I cannot say that people mislead police officers as a matter of course, or often, but investigators must be wary of this possibility.

“Piling on” facts

“A proposition which I took the liberty of doubting.”

“You did, Doctor, but none the less you must come round to my view, for otherwise I shall keep on piling fact upon fact on you until your reason breaks down under them and acknowledges me to be right.”

This is an excellent illustration of what the professional investigator may attempt during an interview, but the person interviewed must not be deprived of their ability to think and must retain an operative mind.

Memory and the work of the investigator

Refresh – Means of doing so: Pinch of snuff!

“‘Your experience has been a most entertaining one,’ remarked Holmes as his client paused and refreshed his memory with a huge pinch of snuff. ‘Pray continue your very interesting statement.’” One hopes that there is little weight assigned to this means of enhancing recall.

Professionalism – Lessons for investigators

Say “sir” and “please”

“I beg that you will not touch me with your filthy hands,” remarked our prisoner as the handcuffs clattered upon his wrists. “You may not be aware that I have royal blood in my veins. Have the goodness, also, when you address me always to say ‘sir’ and ‘please.’”

“All right,” said Jones [of Scotland Yard] with a stare and a snigger. “Well, would you please, sir, march upstairs, where we can get a cab to carry your Highness to the police-station?”

The person detained is always entitled to utmost respect and consideration, on the one hand, and sarcasm by the police is never appropriate.

Misogyny – any bias suffices to destroy value of testimony and to show lack of fairness of investigation

“Had there been women in the house, I should have suspected a mere vulgar intrigue. That, however, was out of the question…” These words by Sherlock Holmes, out of dozens of examples of his misogyny, serve to support a successful defence attack to the effect that he is biased against women.

Various points raised by the story “The Red-Headed League” that are of assistance to investigators

Judgment – Admission – Interpreting words

“It’s all clear,” he whispered. “Have you the chisel and the bags? Great Scott! Jump, Archie, jump, and I’ll swing for it!” What did he mean to say, exactly?

Notetaking – Comparing notes later

“What a time it seemed! From comparing notes afterwards it was but an hour and a quarter, yet it appeared to me that the night must have almost gone, and the dawn be breaking above us…”

One must always be careful to write one’s notes totally separate from others and one of the rare “allowances” for comparison of notes is by the detective in charge putting together the documentation for the prosecution. That does not mean that one asks the officers to explain their perspective, far from it, but rather to point out the obvious features of controversy, such as Officer “A” saw a gun in the rear seat while Officer “B” saw a knife. I recall one case in which the two interviewing officers, one from the RCMP and one from a different force, each testified that the interview took place at their own desk.


I am hopeful that this article will both entertain and assist investigators. I am of the firm belief that one learns about all aspects of police work by reading classic literature and by retaining the lessons it contains on vital subjects such as the dangers of demeanour evidence, the foibles associated with human nature, the concerns that arise when interviewing witnesses and the need for professionalism when having dealings with the general public.


  1. See “A List of One Hundred Legal Novel” (1922), 17 III. L. Rev. 26, at p. 31. Refer as well to this passage from the short story: “You will remember that I remarked … that for strange effects and extraordinary combinations we must go to life itself, which is always far more daring than any effort of the imagination.” Refer as well to Hamlet, by William Shakespeare: “… There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy.” Act 1, sc. v.
  2. Refer as well to a similar article by Law Professor W.H. Hitchler who published these relevant remarks in “The Reading of Lawyers”, (1928) 33 Dick. L. Rev. 1-13, at pp. 12-13: “The Lawyers must know human nature. [They] must deal with types. [They] cannot find all them around… Life is not long enough. The range of [their] acquaintances is not broad enough. For this learning, they must go to fiction. …” I could easily replace “lawyers” by “police officers” and the meaning remains correct.
  3. Interested readers may wish to consult my text, Demeanour Evidence on Trial: A Legal and Literary Criticism, Sandstone Academic Press, Melbourne, Australia, 2008, and two articles: “Demeanour evidence: Guidance from the Tax Court of Canada for Criminal Defence Counsel”, Alan D. Gold Collection of Criminal Law Articles, ADGN/RP-294, May 4, 2020, and “Demeanour Evidence and “Eyelid Turns”: Guidance from the Manitoba Court of Appeal and Anthony Trollope”, Alan D. Gold Collection of Criminal Law Articles, ADGN/RP-293, April 27, 2020.

Gilles Renaud will soon retire after serving 28 years as a member of the Ontario Court of Justice. Previously, he was an Assistant Crown Attorney in Ottawa and a prosecutor with the War Crimes and Crimes Against Humanity Section of the Federal Department of Justice. He began his legal career as a defence counsel and has written nine books on the law, including three in French.

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