The]…police are not immune from liability under the Canadian law of negligence, that the police owe a duty of care in negligence to suspects being investigated, and that their conduct during the course of an investigation should be measured against the standard of how a reasonable officer in like circumstances would have acted. The tort of negligent investigation exists in Canada, and the trial court and Court of Appeal were correct to consider the appellant’s action on this basis. The law of negligence does not demand a perfect investigation. It requires only that police conducting an investigation act reasonably. When police fail to meet the standard of reasonableness, they may be accountable through negligence law for harm resulting to a suspect.

It has not been established that recognizing a duty of care in tort would have a chilling effect on policing, by causing police offic¬ers to take an unduly defensive approach to investigation of criminal activity. In theory, it is conceivable that police might become more careful in conducting investigations if a duty of care in tort is recognized. However, this is not necessarily a bad thing. The police officer must strike a reasonable balance between cautiousness and prudence on the one hand, and efficiency on the other. Files must be closed, life must move on, but care must also be taken…

Recognizing sufficient proximity in the relationship between police and suspect to ground a duty of care does not open the door to indeterminate liability. Particularized suspects represent a limited category of potential claimants. The class of potential claimants is further limited by the requirement that the plaintiff establish compensable injury caused by a negligent investigation. Treatment rightfully imposed by the law does not constitute compensable injury. These considerations undermine the spectre of a glut of jailhouse lawsuits for negligent police investigation.

My colleague Charron J.…states that recognizing tort liability for negligent police investigation raises the possibility that persons who have been acquitted of the crime investigated and charged, but who are in fact guilty, may recover against an officer for negligent investigation. This, she suggests, would be unjust.

This possibility of “injustice” – if indeed that is what it is – is present in any tort action. A person who recovers against her doctor for medical malpractice may, despite having proved illness in court, have in fact been malingering. Or, despite having convinced the judge on a balance of probabilities that the doctor’s act caused her illness, it may be that the true source of the problem lay elsewhere. The legal system is not perfect….