Chapter 2 - Understanding Tunnel Vision


I. Introduction

Tunnel vision in the criminal justice context can be described as a tendency of participants in the system, such as police or prosecutors, to focus on a particular theory of a case and to dismiss or undervalue evidence which contradicts that theory. This mental process leads to “…unconscious filtering in of evidence that will ‘build a case’ against a particular suspect, while ignoring or suppressing evidence respecting the same suspect that tends to point away from guilt.”Footnote 4 It is a collection of mental processes that occur in all human beings and, as such, cannot be prevented merely through education on the topic and/or an effort among justice system participants to attempt to consciously avoid tunnel vision through ordinary practices.

Legal scholars typically include “confirmation bias” as an element of tunnel vision. Confirmation bias is a powerful psychological process that causes an individual to unconsciously prefer information that supports a conclusion that they have already settled on and to disregard or be overly sceptical about information that contradicts that conclusion. While tunnel vision narrows the focus of an investigation to a single target, confirmation bias leads investigators and prosecutors to filter in evidence supporting their theory and to ignore or undervalue evidence that suggests their theory might be incorrect. Confirmation bias causes people to seek, recall, and even interpret data in ways that support their prior beliefs.Footnote 5

“Hindsight bias,” or the “knew-it-all-along effect,” is another psychological phenomenon that affects tunnel vision in criminal investigations and prosecutions. Hindsight bias occurs when a person mixes new information with old information in their brain. This can result in a person believing an event was predictable and they knew it would happen, even if there was no objective evidence for predicting it would occur at the time. The danger of this process in the course of an investigation or prosecution is that when a theory of a case is developed, hindsight bias can lead to a “rejudgment process that the given outcome seems inevitable or, at least, more plausible than alternative outcomes.”Footnote 6 Studies have shown that hindsight bias can also affect judgements about accused persons’ past conduct, making the current allegations against them seem all the more probable. Footnote 7

In addition to unconscious biases, human psychology also tells us that individuals typically rely on a host of cognitive heuristics or mental shortcuts to make decisions, even complex ones.Footnote 8 Decision makers - even the best, the brightest and the highly principled - do not have unlimited mental capacity to process each piece of information that is presented to them in a problem, assign the level of importance each piece has on the decision as a whole, consider all the available alternatives, and then engage in a complex mental algorithm to arrive at their decision. Indeed, research suggests that as the demands on limited cognitive resources increase, the more likely it is that decision-makers will employ cognitive heuristics or other strategies intended to reduce the amount of mental effort required to arrive at a decision.Footnote 9 In such cases, the decision-maker is often (unconsciously) seeking a satisfactory solution, rather than an optimal one. An exploratory piece of research conducted by Islam, Weir and Del Fiol (2014),Footnote 10 examined decision making in expert clinicians and found they use mental shortcuts in complex cases, particularly when they are faced with significant time constraints, multiple interruptions and simultaneous demands. Police and prosecutors across Canada also routinely make decisions under similar conditions. When these conditions are coupled with high or unmanageable caseloads, it is easy to see how an over-reliance on cognitive heuristics and biases could open the door to the effects of tunnel vision.

The general process of a criminal investigation in Canada may also increase the likelihood of tunnel vision occurring. Typically, prosecutors receive a developed case full of evidence implicating the accused. They are not usually provided with evidence that might implicate other suspects or is otherwise inconsistent with the investigator’s theory of the case. Prosecutors must be extremely vigilant and willing to challenge the investigation in order to guard against the effects of tunnel vision. As discussed in the previous Reports, several Canadian commissions of inquiry have indicated tunnel vision is a leading cause of wrongful convictions.

II. 2011 Recommendations

While the 2005 Report’s recommendations remain valid, the Subcommittee recommended slight refinements as follows:

  1. Crown policies on the role of the Crown should emphasize the quasi-judicial nature of the position and the inherent danger of adopting the viewpoints or enthusiasm of others without thorough analysis. Policies should encourage prosecutors to remain open to alternate theories proffered by defence counsel or other credible parties.
  2. Where geography and resources permit, jurisdictions should consider implementing a best practice whereby a prosecutor who had significant pre-charge involvement is replaced by another prosecutor to maintain carriage of the file post-charge.
  3. In jurisdictions without pre-charge screening, charges should be reviewed by prosecutors as soon as practicable and an ongoing critical assessment must be made.
  4. Second opinions and case reviews should be available in all areas.
  5. Internal organizational accountability should be clearly defined and understood. Prosecutors must understand their role in each prosecution and the respective role of their supervisors.
  6. A Crown culture which encourages discussion and contrarian thinking should be cultivated in Crown Law offices.
  7. Law enforcement agencies and prosecutors play complementary roles in the criminal process. While they both enjoy institutional independence at their respective stage of the process, it does not preclude cooperation and mutual assistance to strive for justice.
  8. Training for prosecutors and police on the prevalence and prevention of tunnel vision should be implemented. Prosecutors and police should have a clear understanding of each other’s role in the criminal justice system.

III. Institutional Pressures That Reinforce Tunnel Vision

As discussed above, tunnel vision stems from a group of naturally occurring cognitive biases and shortcuts to which all humans are susceptible. Furthermore, these cognitive biases tend to arise more readily in the justice system when the circumstances of the offence or the accused offender are susceptible to extraneous environmental factors, such as widespread public outrage, being perceived as an “outsider,” or from a disadvantaged, unpopular or minority group. These cognitive biases can also be reinforced by internal pressures which are endemic to the justice system. This section examines several of these pressures which may serve to reinforce tunnel vision in unsuspecting justice system participants.

a) Pressure on Prosecutors and Police

Prosecutors are instructed that obtaining a conviction is never their primary goal and that their quasi-judicial function “excludes any notion of winning or losing.”Footnote 11 However, there remain institutional pressures including pressure from victims and their families, the public, colleagues, and supervisors to obtain a conviction.Footnote 12 The long-term impact of these pressures can contribute to a “conviction psychology” where a prosecutor’s mentality shifts from doing justice towards obtaining convictions. This may be influenced by the fact that Crowns must believe there is a reasonable or substantial likelihood of conviction in order for a case to proceed to trial. However, studies reveal that prosecutors do tend to develop a conviction psychology over time.Footnote 13 Interestingly, each of the Crown counsel in the well-known wrongful convictions of Donald Marshall, Guy-Paul Morin, David Milgaard, Thomas Sophonow, and James Driskell were lawyers with lengthy trial experience.Footnote 14

Policing agencies are also exposed to intense public pressure and media scrutiny in the course of their investigations, particularly when the alleged crime is violent or disturbing in nature, and there is reason to believe the offender remaining at large poses a risk to the safety of others. In these instances, police are working to identify a suspect quickly and, as a result, may succumb to tunnel vision by prematurely focussing their investigation on one person and ignoring other potential leads or lines of inquiry.

Policing culture that fosters competition between team members also hinders open communication and collaboration in a case. Further, it is important for police agencies to guard against a “win at all costs” culture in terms of solving crime: not all crimes can be solved and the temptation to cut investigative corners or to engage in conduct that violates Charter rights must be zealously discouraged. Investigators must accept that it is better to let a suspect evade prosecution than to engage in unacceptable conduct such as “noble cause corruption.” To do otherwise can also promote tunnel vision amongst investigators who do not want to admit if they made a mistake. Justice Fred Kaufman in the Commission on Proceedings Involving Guy Paul Morin (1998)Footnote 15 recommended that investigators should not receive elevated standing in an investigation via acquiring or pursuing the “best” suspect or lead, as this is detrimental to the sharing of critical information between teams. Management in policing agencies must also take responsibility for creating a work environment that values open, honest and fair investigation, that protects the rights of suspects and accused persons, and that supports constant as well as continuous fact verification.Footnote 16

b) Changing Prosecution Trends

The true enemy of tunnel vision is thorough, objective thought. Although crime has been on a downward trend in Canada since the 1990s, the demands that have been placed upon Crown prosecutors across the country have dramatically increased, limiting time for important case analysis in some instances. For example, the number of court appearances required to resolve a matter has been on the rise nationwide, consuming precious prosecution resources. Footnote 17 Technology and forensic science have evolved in leaps and bounds, resulting in much larger volumes of evidence to process, and posing serious challenges to providing full disclosure in a timely manner. Some have suggested that the introduction of new mandatory minimum sentences provides incentive for more matters to go to trial, and the trials that proceed have become longer and more complex.Footnote 18 Additionally, the R. v. Jordan decision on trial delays by the Supreme Court of Canada adds further strain to an already overburdened system, holding the Crown accountable for moving cases forward as quickly as possible.

c) Noble Cause Corruption, Trauma and Tunnel Vision

In the literature on tunnel vision, much has been written about “noble cause corruption” and how it may lead to wrongful convictions. Noble cause corruption occurs when investigators and/or prosecutors focus on an end result (such as apprehending or convicting a suspect), and engage in unethical or perhaps even unlawful activities to achieve that result (such as using excessive force, or suppressing adverse forensic reports).Footnote 19 In such instances, justice system participants may be responding to public pressure, or they may be emotionally invested in a case and driven by the need to protect the victim or society from the suspected perpetrator, and so they will do “whatever it takes” to secure a conviction. It is important to note that these individuals believe they are working in the public interest and are generally not dishonest or unethical people. Some aspect of the case, however, is causing them to make emotional decisions rather than engaging in impartial and principled thought. A Canadian research study, for example, suggests that investigators who regularly deal with child and elder abuse are more tolerant of noble cause corruption, and may themselves engage in this behaviour.Footnote 20 In these instances, the police and/or the Crown have an accused in their sights, and want to “put him away.” This mindset is an extension of tunnel vision by distorting any new information these individuals may receive. It may also be the result of vicarious trauma.

“Vicarious trauma,” or secondary trauma, occurs when an investigator or Crown prosecutor begins internalizing a victim’s traumatic experience. Prolonged exposure to graphic images of crime scenes, for instance, or disturbing accounts of violence and cruelty, may intrude on a professional’s daily life and cause considerable distress.Footnote 21 Vicarious trauma is a cumulative process that occurs over time, and often affects individuals who feel responsible, committed and care deeply about their work.Footnote 22 Some of the more common symptoms of vicarious trauma include feelings of numbness or hyper-arousal, difficulty managing emotions, difficulty making good decisions, and problems managing boundaries between yourself and others. Therefore, when a professional who is experiencing vicarious trauma is left to deal with a particularly horrific case, they may not understand that their decision-making ability has been compromised. They may also employ tunnel vision (unconsciously) as a means of coping with the situation by focusing on getting the accused off the street and behind bars, rather than objectively reviewing all the available information in the matter.

Traditionally, research on vicarious trauma has focused on social workers, psychologists and first responders. In fact, many police services across the country recognize how this issue affects their officers and have programs in place to help. Additionally, provinces such as Saskatchewan, Alberta, Manitoba, Ontario, British Columbia and the Yukon have implemented various forms of juror support programs for jury members who are exposed to traumatic material in court.Footnote 23 At the federal level, the House of Commons Standing Committee on Justice and Human Rights undertook a study of counselling and other mental health supports for jurors and found that those who witness a traumatizing event or hear details about it can later be diagnosed with PTSD and vicarious trauma. The report recommended that the federal Minister of Justice encourage the provinces and territories to offer a psychological support and counselling program to all jurors after their jury service has ended.Footnote 24

Mental health assistance for prosecutors and family law lawyers has not been as forthcoming, despite ongoing and chronic exposure to the same distressing material, but this is beginning to change as we understand how vulnerable these professionals can be to this form of trauma. Research has found that rates of vicarious trauma among U.S. attorneys were almost five times higher than that of other professions.Footnote 25 Furthermore, a study published in the Pace Law Review found that lawyers working with victims of domestic violence and criminal defendants experienced significantly higher levels of vicarious trauma than social workers and mental health professionals. This difference appeared to be the result of the lawyers’ higher caseloads and lack of education around vicarious trauma and its effects.Footnote 26

Justice professionals do not have to experience vicarious trauma to engage in noble cause corruption or tunnel vision. However, it is clear that undiagnosed, traumatized individuals are more susceptible to its effects. If Crowns do not truly understand what vicarious trauma is or how it can affect their work, they may not be able to recognize when it is having a detrimental effect on their case analysis or decision making. Providing further training in this area and taking greater care in managing Crown caseloads could assist with warding off the two-headed spectre of noble cause corruption and tunnel vision in criminal matters.

IV. Court Commentary on Tunnel Vision Since 2011 Report

A review of “tunnel vision” commentary by Canadian courts (since 2011) suggests this topic is most often raised by defence counsel regarding the quality of the police investigation that was conducted in a criminal matter. The following cases include examples of such commentary:

a) R. v. Iskander, 2017 ABPC 191Footnote 27

This matter involved allegations of sexual assault and is subject to a publication ban. It resulted in a judicial stay, and the court offered some commentary about the lead detective in the matter, who, the court found, was suffering from tunnel vision in his investigation.

Did [the investigator] suffer from “tunnel vision” (“a single-minded and overly narrow focus on a particular investigative theory”) in this investigation?

[80] I find that he did. The issue in the Morin case was the identity of the perpetrator. Here, the issue was whether the acts the Accused allegedly committed, in fact, occurred. [The investigator] clearly believed they did and his investigation had a single-minded and overly narrow focus on his belief.

[92] [The investigator] later offered this: “Hearing from witnesses to date, there is a large divide in the church community and [the Accused] is allegedly still providing false information to the community targeting the victims and their families.”

[93] When questioned during this hearing about what he meant by the Accused “providing false information to the community”, [the investigator] conceded that he had heard from witnesses that the Accused was telling people he was innocent of the charges.

[94] Perhaps no other piece of evidence amongst the testimony and 27 documentary exhibits produced at this hearing demonstrates as clearly as these comments that [the investigator], even though he “understands the presumption of innocence”, suffered from tunnel vision.

b) R. v. Fries, 2017 MBCA 58Footnote 28

This appeal concerned a second degree murder conviction. The accused argued that the verdict was unreasonable because the absence of evidence provided the alternative inference of someone else committing the murder. The appeal was dismissed by the Manitoba Court of Appeal:

[11] While the accused did not testify, he advanced the defence through counsel that someone else stabbed the victim to death after his fight with him and that the police had tunnel vision by focussing their investigation on the accused alone as they did not have DNA analysis done on all of the exhibits seized.

[16] Also, the challenge to the adequacy and objectivity of the police investigation is nothing but supposition, given the record.  We have no doubt, as a general proposition, that competent defence counsel will vigorously pursue forensic analysis of any evidence if they have a true concern of the police having tunnel vision in their investigation and results of forensic testing of evidence may exonerate an accused.  For defence counsel to fail to do otherwise would risk a wrongful conviction of their client.

[17] It is difficult to see how the police had tunnel vision here when the exhibit officer testified that, if the defence had asked that a particular exhibit seized be forensically examined by the RCMP lab, she saw no reason why the Winnipeg Police Service would not have made that request to the RCMP lab. Moreover, section 605 of the Code allowed the accused to obtain custody of any exhibit seized by the police for independent scientific testing if the police had been unable or unwilling to assist, or the defence did not want the police involved in any way in the testing process.  It is noteworthy, for the purposes of disposing of this appeal, that there is no suggestion by appellate counsel that the defence counsel at trial was incompetent by not pursuing forensic analysis of exhibits gathered in the police investigation that were not selected and sent to the RCMP lab for forensic analysis by the investigators.

c) R. v. Richards, 2015 ABQB 617Footnote 29

This case involves two accused who were charged with manslaughter and kidnapping. Counsel for the accused allege that the police investigation was tainted by tunnel vision.

[373] Having reviewed the evidence carefully as a whole, and having paid particular attention to the investigatory process outlined by [the investigator] in his evidence, both in chief and during cross-examination, the Court rejects the accuseds’ submission that the investigation was tainted by tunnel vision.

[374] The Court has outlined the testimony of [the detective] above. While there were a number of leads that CPS devoted less than full resources to, this does not cause the Court to conclude that the investigation was tainted by tunnel vision.

[402] In R v Zoraik, 2010 BCPC 472 (CanLII); conviction upheld on appeal: 2012 BCCA 283 (CanLII), the Court discussed the interplay between tunnel vision and the Crown’s burden, stating, at para 81:

It is important to not lose sight of what is in issue when tunnel vision is part of the defence attack on the police investigation. The police investigation is not on trial. Nor should the strategic decisions the police make be subject to minute after-the-fact analysis. What is in issue is whether a reasonable doubt is created because the police investigation has failed to bring before the court a complete and persuasive picture of what occurred. It may be of interest that tunnel vision led to an incomplete investigation. But the issue nevertheless remains whether the evidence presented is complete so as to satisfy the burden of proof. The focus should be no more and no less.

[403] Defence Counsel alleged numerous deficiencies in the police investigation. The Court has found the allegations as to tunnel vision during the investigative process to be groundless. The manner and method of investigation described by [the investigator] and other officers does not suggest that relevant information was ignored or suppressed.

d) R. v. Caron, 2014 BCCA 111Footnote 30

This appeal involved an accused who was convicted of sexual assault, unlawful confinement and uttering threats of death or bodily harm, and is subject to a publication ban. A key issue at trial involved the identification of the individual who attacked the complainant. Potential investigative tunnel vision was also examined and dismissed by the court. The conviction was upheld.

[35] Lastly, Mr. Caron submits the trial judge did not address the adequacy of the police investigation, or investigative tunnel vision. He points to the failure of the police to follow up on the identity of the male at the medical clinic; the failure to follow up on two other possible suspects, one who may have fit the complainant’s description of her attacker; the unfair photo line-up containing only headshots of dark haired men wearing no glasses; the police looked only for a local blue Ford Ranger truck, although it was Canada Day weekend with a large influx of tourists into the area; and there was no investigation into the uniqueness of the type of tread pattern on the windshield or a bare foot impression on the windshield.

[50] The final argument Mr. Caron raises concerns the nature of the police investigation. He submits that the evidence regarding the shoeprints was tainted by investigative “tunnel vision”, which when taken in conjunction with the arguments addressed above establishes that the verdict was unreasonable.

[51] When determining whether an investigation has been tainted by “tunnel vision”, the concern is whether the accused person was limited in his ability to make full answer and defence. This could include whether the Crown failed in its disclosure obligations or whether the police negligently or deliberately ignored evidence that the offence might have been carried out by any person other than the accused: R. v. Wilkinson, 2010 BCCA 316 (CanLII) at para. 40.

e) R. v. Chapman, 2013 BCPC 232Footnote 31

The matter involved an allegation of physical assault against a young child (L.M.) who was three years old. The accused was acquitted of the charge. In the Reasons for Judgment, the court offers some commentary about tunnel vision and victim advocacy.

[27] In the present case, I have noted the high level of concern and involvement of L.M.’s immediate and extended family, most of whom have attended during the several days of trial.  It is clear to me that emotions are high.  My previously referenced observations about family member’s testimony makes clear to me the family have made up their mind Mr. Chapman is guilty and that they want to procure a conviction. That emotions are high is very understandable when a loving family believes one of their young and vulnerable has been victimized by an adult.  It is this type of emotional backdrop that can lead people to have what is referred to as ‘tunnel vision’.

[28] Tunnel vision is when people convince themselves a theory is true, and then focus only on consistent evidence, and disregard evidence that is inconsistent with the theory. Tunnel vision can happen not only to concerned and emotionally involved family members, but there have been several regrettable high profile cases in Canada where it has been later established the accused were wrongfully convicted as a result of the tunnel vision of the justice system professionals. I hasten to add that there is no evidence of tunnel vision on the part of the police or Crown in this case, and that this was a case properly brought to trial. My above discourse is for the benefit of the family, and to emphasize that it is the responsibility of a trial judge to take into consideration all of the admissible evidence in determining whether the evidence establishes guilt beyond a reasonable doubt.

f) Auclair c. R., 2011 QCCS 2661Footnote 32

This matter was a mega-case which involved a group of 155 individuals who were alleged to be members of the Hells Angels. These individuals (the petitioners) were seeking either a stay of the proceedings for abusive prosecution, or the quashing of the direct indictment. The respondent in the matter was the Director of Criminal and Penal Prosecutions. The commentary the court offers on the subject of tunnel vision is both comprehensive and enlightening.

Loss of objectivity - adoption of tunnel vision

[64] The petitioners argued that the respondent, even before analyzing the evidence, adopted the police theory. The adoption of that preconceived idea resulted in the prosecution’s loss of objectivity. The danger of tunnel vision was described in Chapter 4 of the Report on the Prevention of Miscarriages of Justice, prepared by the F.P.T. Heads of Prosecutions Committee:

Tunnel vision has been defined as “the single minded and overly narrow focus on an investigation or prosecutorial theory so as to unreasonably colour the evaluation of information received and one’s conduct in response to the information.” Tunnel vision, and its perverse by-product “noble cause corruption,” are the antithesis of the proper roles of the police and Crown Attorney. Yet tunnel vision has been identified as a leading cause of wrongful convictions in Canada and elsewhere.

[65] According to the petitioners, the adoption of tunnel vision in this case is proven by the close collaboration between police and prosecutors during the investigation; by the use of a legal theory referring to criminal responsibility that is not supported by the literature or jurisprudence; by the abandonment of the prosecutors’ traditional role as prosecutor and their assumption of the role of investigator, as shown by the hours of meetings with certain special witnesses; by the absence of a critical sense; and by the premature arrests.

[66] After studying the evidence, the Court concludes that the petitioners did not prove, on a balance of probabilities, that the respondent either had tunnel vision or failed in its duty to be objective. Let us look at the arguments advanced by the petitioners.

[67] They complained of close collaboration between police and prosecutors, who went so far as to share the same premises for months before the arrests. The evidence certainly shows that that was true, but the Court concludes that that was understandable, given the scope of the case. The various studies produced by the petitioners are unanimous in recognizing that, in mega-investigations and mega-trials, it is essential that there be greater complicity between the investigators and the prosecutors.

[68] The petitioners failed in their attempt to show that the prosecutors went beyond merely providing legal opinions to the police and actually conducted investigations. The Court stresses at this point that the petitioners’ attorneys repeated many times during the hearing of the motion that they did not doubt the good faith of the Director’s prosecutors. There is no evidence to support the inference that the respondent’s prosecutors abandoned their traditional role and took on that of investigator.

[69] The police witnesses were unanimous: the prosecutors never directed the investigation because that was not their role; only the prosecutors decided on the charges to be brought and against whom; those decisions were made after days of meetings between prosecutors.

[70] Given the scope of the case and the important role attributed to the special witnesses, it is not surprising that the prosecutors met with some of them for hours before the laying of charges. The petitioners conceded that it was legitimate for the prosecutors to determine whether the special witnesses, and especially Boulanger, were credible and reliable in their eyes. Furthermore, in the Court’s opinion, considering the period of time covered by the charges and the potential number of accused, it is understandable and acceptable for the prosecutors to want to review those facts with the potential witness. That the review resulted in requests for further investigations is neither surprising nor unreasonable.

V. Mitigating Tunnel Vision

Although many institutional pressures in the justice system may exacerbate tunnel vision, there are also a number of mitigating strategies and protective factors that can assist in preventing this insidious effect. This section will examine some of these elements.

a) Major Case Management Methodology and Training for Police

The Major Case Management (MCM) Model was developed in 1994 by the Canadian Police College, refined over time, and has since become an accepted “best practice” for managing serious investigations.Footnote 33 MCM methodology is used by agencies such as the RCMP and the Vancouver Police Department and has also received strong endorsement from the judiciary. Justice Archie Campbell’s Bernardo Investigation Review,Footnote 34 as an example, explicitly encourages police to take MCM training, as it provides a solid framework investigators can use to overcome the innumerable challenges that come with major incident investigations. Correctly applying the nine principles of MCM can prevent tunnel vision at the outset of an investigation by ensuring it is conducted professionally, strategically and ethically. Currently, British Columbia has a Major Case Management Team Commander accreditation process and those personnel selected to lead major investigations are typically accredited Team Commanders.

Quality police training in general plays an important role in preventing tunnel vision in the justice system. While many agencies, including the RCMP, do not offer courses which are specific to wrongful convictions, many investigative courses do cover related topics such as tunnel vision. Further, the MCM training summarized above considers failed investigations - including those that resulted in a wrongful conviction - and its systematic approach and emphasis on use of best practices and ethical decision-making lends itself well to preventing wrongful convictions. Chapter 7 of this Report outlines the results of a recent survey which examined police and prosecutor training across Canada on the issue of wrongful conviction course content, and tunnel vision specifically. While 100 percent of responding police agencies indicated their training included tunnel vision subject matter, only 50 percent of responding police training institutes indicated that their courses had some material on tunnel vision, indicating that considerable training occurs within police agencies, rather than relying on provincial police training institutions. With respect to Crown training, 75 percent of the responding prosecution services indicated they provide training with tunnel vision course content.

b) Wrongful Conviction Risk Assessment Checklist

The International Association of Chiefs of PoliceFootnote 35 has crafted a checklist to assist investigators in identifying “red flags” in their cases:

Prince Edward Island Footnote 36 has developed a guide for prosecutors to critically assess the strength of their case that includes the following questions:

  1. Are there grounds for believing that some evidence may be excluded?
  2. If the case depends in part on admissions by the accused, are there any grounds for believing that they are of doubtful reliability having regard to the age, intelligence and apparent understanding of the accused?
  3. Does it appear that a witness is exaggerating, or that his or her memory is faulty, or that the witness is either hostile or friendly to the accused or may be otherwise unreliable?
  4. Has a witness a motive for telling less than the whole truth?
  5. Are there matters which might properly be put to a witness by the defence to attack his or her credibility?
  6. Based on objective indicators, what sort of impression is the witness likely to make?
  7. How is the witness likely to stand up to cross-examination?
  8. If there is conflict between eye witnesses, does it go beyond what one would expect and hence materially weaken the case?
  9. If there is a lack of conflict between eye witnesses, is there anything which causes suspicion that a false story may have been concocted?
  10. Are all the necessary witnesses competent to give evidence?
  11. Where child witnesses are involved, are they likely to be able to give sworn evidence or to give evidence based upon a promise to tell the truth?
  12. If identity is likely to be an issue, how cogent and reliable is the evidence of those who purport to identify the accused?
  13. Where two or more accused are charged together, is a there a reasonable prospect of the proceedings being severed? If so, is there sufficient evidence against each accused, should separate trials be ordered?

A wrongful conviction assessment guide or checklist is a practical tool that helps prevent tunnel vision by encouraging the open-minded review of cases.

c) Independence and the Prosecution Service

While public pressure has been described as a factor that can lead to tunnel vision in a criminal matter, the principle of prosecutorial independence is a fundamental tenet of our legal system and can serve to insulate prosecutors from making decisions that may be popular, but incorrect. In preventing wrongful convictions, prosecutors must be objective, impartial and non-partisan in their decision-making. Crowns cannot be swayed by public opinion or compelled by government officials to make hasty decisions, or, as history tells us, tunnel vision and wrongful convictions can be the result.

Prosecution services across Canada are expected to operate independently of partisan concerns and this goal has been achieved in two ways - either through legislation or through convention. Nova Scotia, British Columbia, Quebec and the Public Prosecution Service of Canada all have legislatively independent prosecution services, transferring responsibility for criminal prosecutions away from the (elected) Attorney General, and toward an appointed head of the prosecution service. This, it may be argued, reduces political pressure on the Attorney General and Minister of Justice, and safeguards prosecutorial discretion. Nova Scotia is the oldest of the statutory-based independent prosecution services, and sought its independence following an inquiry into the wrongful conviction and incarceration of Donald Marshall Jr., whose case involved elements of tunnel vision. Since that time, Nova Scotia’s prosecution service has been subject to at least three reviews, all of which have supported legislative independence. In the third review, known as the Westray Prosecution Review, the independence of the service was truly tested after the Crown decided not to proceed with the prosecution of the operators of the Westray mine, which exploded in 1992, killing 26 miners and provoking considerable public outrage. The review concluded: “the decision to stop the prosecution was based upon a consideration of appropriate factors.”Footnote 37

The remaining prosecution services across Canada remain independent by convention, meaning that the Ministers of Justice and Attorneys General generally do not become involved in the prosecution of cases before the courts, although they have the power to do so. The Attorney General, however, like Crowns, also has a constitutional obligation to act independently of partisan concerns and other improper motives. This fact was recently re-emphasized in the 2016 Supreme Court of Canada R. v. CawthorneFootnote 38 decision:

The Minister, like the Attorney General or other public officials with a prosecutorial function, is entitled to a strong presumption that he exercises prosecutorial discretion independently of partisan concerns. The mere fact of the Minister’s membership in Cabinet does not displace that presumption. Indeed, the law presumes that the Attorney General — also a member of Cabinet — can and does set aside partisan duties in exercising prosecutorial responsibilities. [32]

Therefore, whether independent by legislation, or independent by convention, prosecutors across Canada are expected to make their decisions in an objective, professional manner, uninfluenced by public pressure or any other factor that is irrelevant to the case. The principle of the independent, objective prosecutor is one of the surest safeguards against tunnel vision in the system. It must be supported and upheld at all times, particularly by “those responsible for the daily operation and public repute of the criminal justice system.”Footnote 39

d) Pre-charge Consultation and Collaboration

Close collaboration and open communication between Crown and police in the early stages of a case is another way of mitigating tunnel vision in both parties. Although it is important for police and Crown to maintain separate and distinct roles in the criminal justice system, it is just as important for them to work collaboratively by sharing information with one another, while the evidence in a matter is still “fresh,” and alternative theories and suspects may still be vigorously pursued. Although tunnel vision experts such as MacFarlane warn against the blurring of lines between police and Crown, early discussions and consultations about a case does not necessitate the loss of objectivity if both participants keep an open mind. Furthermore, cases such as R. v. Ahluwahlia demonstrate that while prosecutors may rely on the police to investigate matters, the courts expect the Crown to “poke and prod” investigators to ensure tunnel vision has not set in for either party.Footnote 40

The level of expected pre-charge consultation and collaboration differs significantly between law enforcement agencies and the various prosecution services across Canada. It is worth noting that British Columbia, New Brunswick, and Quebec adhere to a pre-charge system, which requires that a Crown prosecutor reviews and approves charges before the police lay an information in a matter. In these provinces, the Crown who recommends and approves charges is sometimes different from the Crown who is assigned to prosecute the case. (In Quebec, this process is only possible in large centres.) This separation adds additional perspective to the matter and offers further protection against tunnel vision.

The remaining provinces and territories adhere to a post-charge system, which does not mandate any level of consultation before charges are laid. However, in many post-charge provinces, the prosecution services have forged close connections with their policing counterparts, and communication and collaboration during the investigative stage is not unusual between these two groups. Alberta, as an example, has Pre-charge Consultation Protocols in place with all the policing services across the province that ensures consultation takes place in serious and violent matters, and/or in cases with complex evidentiary requirements or complex search warrants. This is another way of promoting an organized and collaborative approach to reviewing evidence in a case, without fundamentally changing the dynamics between police and Crown.

e) Devil’s Advocate Position

Crown prosecutors are taught to be contrarian thinkers, which is a protective factor against tunnel vision. However, when work stress and pressures begin to add up, even the most independent prosecutor can fall victim to this effect. This necessitates making contrarian thinking a more formalized process in Crown Offices by developing a “contrarian” or “devil’s advocate” position. The role of the devil’s advocate would be to review major cases separately from those in charge of the prosecution. An individual in this position would intentionally approach their review of the case from the perspective that the accused is innocent and would view evidence to the contrary as disconfirming evidence of their theory. The value of this position is two-fold: 1) it prevents the devil’s advocate from having the prosecutor and investigator’s theory of the case reinforced via direct communication and 2) it combats the institutional pressures that Crown prosecutors feel by being placed in a unique role that is free of the expectations of victims, the public, and their colleagues.

This position is not a new idea and has been discussed before in high-profile inquiries in Canada such as the Morin Inquiry. Footnote 41 Further, the role of the “contrarian” is a component of the Major Case Management model taught at the Canadian Police College and has been successfully used by policing agencies to prevent tunnel vision and “premature investigative conclusions.”Footnote 42

VI. Tunnel Vision in Prosecution Policy

Some prosecution services across Canada explicitly address tunnel vision in their guidelines to Crown. These guidelines, and their instruction to prosecutors, are:

Prosecution Service

Public Prosecution Service of Canada (Includes Nunavut, the Yukon and the Northwest Territories)


Prevention of Wrongful ConvictionsFootnote 43

Reference to Tunnel Vision

Includes an entire section dedicated to the discussion of tunnel vision. Encourages Crowns to act as gatekeepers and critically review all available evidence, to seek out second opinions, and to foster a work environment that embraces questions, consultations and frank debate. Mentoring is mentioned as an important tool in understanding the role and the independence of the Crown.

Prosecution Service



Decision to ProsecuteFootnote 44

Reference to Tunnel Vision

Emphasizes the importance of seeking a second opinion from prosecutors who are uninvolved with a case to prevent tunnel vision from occurring.

Prosecution Service

Newfoundland and Labrador


Duties and Responsibilities of Crown AttorneysFootnote 45

Reference to Tunnel Vision

Policy notes the Crown has a duty to be fair and to appear as fair, and as such, they must carefully guard themselves against tunnel vision and of practicing “overzealous” or “overreaching” advocacy. They must also remain open to alternate defence theories and remain free of partisan influences.

Prosecution Service

Prince Edward Island


Guidebook of Policies and Procedures for the Conduct of Criminal Prosecutions In Prince Edward IslandFootnote 46

Reference to Tunnel Vision

Instructs Crowns to guard against being inflicted by “tunnel vision” through close contact with the investigative agency, colleagues or victims.

Other Prosecution services, including British ColumbiaFootnote 47, SaskatchewanFootnote 48, ManitobaFootnote 49, OntarioFootnote 50 and Nova ScotiaFootnote 51 provide guidelines that define the role of the prosecutor in the justice system, and the importance of being independent, objective, dispassionate, free from outside influences and measured in their approach. QuebecFootnote 52 provides a directive to prosecutors which requires them to keep an open mind and constantly re-evaluate new evidence when they proceed with a prosecution. New Brunswick’sFootnote 53 Legal Advice to Police policy warns Crowns not to become too involved in an investigation lest they lose their objectivity. Being mindful of their duties, and comfortable with their role in the justice system is essential for any prosecutor in the fight against tunnel vision.

VII. Updated Recommendations

The 2005 and 2011 Reports made eight recommendations that may assist in reducing tunnel vision in law enforcement and Crown prosecution agencies. These recommendations were as follows:

  1. Crown policies on the role of the Crown should emphasize the quasi-judicial nature of the position and the inherent danger of adopting the viewpoints or enthusiasm of others without thorough analysis. Policies should encourage prosecutors to remain open to alternate theories proffered by defence counsel or other credible parties.
  2. Where geography and resources permit, jurisdictions should consider implementing a best practice whereby a prosecutor who had significant pre-charge involvement is replaced by another prosecutor to maintain carriage of the file post-charge.
  3. In jurisdictions without pre-charge screening, charges should be reviewed by prosecutors as soon as practicable and an ongoing critical assessment must be made.
  4. Second opinions and case reviews should be available in all areas.
  5. Internal organizational accountability should be clearly defined and understood. Prosecutors must understand their role in each prosecution and the respective role of their supervisors.
  6. A Crown culture which encourages discussion and contrarian thinking should be cultivated in Crown Law offices.
  7. Law enforcement agencies and prosecutors play complementary roles in the criminal process. While they both enjoy institutional independence at their respective stage of the process, it does not preclude cooperation and mutual assistance to strive for justice.
  8. Training for prosecutors and police on the prevalence and prevention of tunnel vision should be implemented. Prosecutors and police should have a clear understanding each other’s role in the criminal justice system.

Additionally, the Subcommittee suggests the following new measures:

  1. Information on vicarious trauma should be provided to Crown prosecutors. Crowns should understand the symptoms of vicarious trauma, and how it affects the decision making-process. Those affected should receive appropriate support.
  2. Where resources permit, prosecution services should consider formalizing the “devil’s advocate” position in Crown offices and on Crown Prosecutions Teams.
  3. Case assessment tools or guidelines aimed at preventing wrongful convictions should be developed by the Federal/Provincial/Territorial Heads of Prosecutions Subcommittee on the Prevention of Wrongful Convictions, for consideration by prosecution services across the country.
  4. Tunnel vision guidelines and policies should be developed by police and prosecution services which don’t currently have them.
  5. Police services should be encouraged to continue to support delivering MCM training to those involved with major case investigations, as such training specifically addresses causes of failed investigations and gives strategies to mitigate them.
  6. Other jurisdictions should be encouraged to consider British Columbia’s Major Case Management Team Commander accreditation process as a method to ensure only highly qualified personnel are assigned to lead major investigations.


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