The legal authority to arrest

The security office at Harbour Mall is a small room behind the pharmacy with two chairs, a desk and a bank of camera monitors. When Reyes and Malhotra arrived at 16:31, Dana Whitcomb was sitting in one of the chairs with her coat on her lap, and Callum Price, the loss prevention officer, was standing by the door. A plastic basket on the desk held the cosmetics and vitamins she had walked out with. Price had already told her that she was being held for police. Reyes's first question to Price was the one Desjardins wants every student to ask first: 'What did you see, and what authority did you act under?'

Desjardins tells the class that an officer who cannot answer the question 'what is my authority?' should not take the next step. Authority comes from statute and from the common law as interpreted by the courts. It sets out who may arrest, for what kind of offence, on what standard of belief, and with what limits. An arrest made without authority is unlawful, and an unlawful arrest has consequences that ripple through everything that follows: the searches that came with it, the statements the person made and the force used to make it.

Arrest by a private person

Section 494 of the Criminal Code allows anyone to arrest without a warrant a person they find committing an indictable offence, or a person they believe on reasonable grounds has committed a criminal offence and is escaping from and freshly pursued by people with lawful authority to arrest. The owner of property, a person in lawful possession of it, or someone they authorize, such as a loss prevention officer, may also arrest a person they find committing a criminal offence on or in relation to that property. Since the Citizen's Arrest and Self-defence Act came into force in 2013, that property-owner power also extends to an arrest made within a reasonable time after the offence, if the arrestor believes on reasonable grounds that it is not feasible for a peace officer to make the arrest. Anyone who makes an arrest under section 494 must deliver the person to a peace officer forthwith.

Price told Reyes that he had watched Whitcomb on camera putting items into her bag in the cosmetics aisle, then followed her past the last point of sale and out the doors. He stopped her about ten metres outside, identified himself, and asked her to come back inside, which she did. He had not searched her bag; she had taken the items out herself and put them in the basket. Reyes wrote it all down. 'His account matters because our authority builds on his,' Malhotra told her later. 'If he got it wrong, we inherit the problem.'

Malhotra explained that Price's arrest was lawful under section 494(2) because he found her committing a theft in relation to the store's property, and that he had done what section 494(3) requires by calling police immediately and holding her only until they arrived. Once Reyes and Malhotra arrived, the next question was their own authority.

A peace officer's power to arrest

Section 495(1) of the Criminal Code allows a peace officer to arrest without a warrant a person who has committed an indictable offence or who, on reasonable grounds, the officer believes has committed or is about to commit an indictable offence; a person the officer finds committing any criminal offence; or a person for whom the officer has reasonable grounds to believe a warrant is in force. Hybrid offences, which the Crown can prosecute either by indictment or summarily, count as indictable for the purpose of arrest until the Crown makes its choice. Theft under 5,000 dollars is a hybrid offence, so Reyes had a power to arrest Whitcomb on reasonable grounds.

Reasonable grounds have two parts, as the Supreme Court of Canada explained in R. v. Storrey in 1990. The officer must actually believe the person committed the offence, and that belief must be objectively reasonable, meaning a reasonable person standing in the officer's shoes would also believe it. Reasonable grounds do not require proof beyond a reasonable doubt or even a prima facie case; they require a reasonable probability based on the facts known to the officer. Reyes had Price's direct observations, the camera footage he showed her and the items in the basket.

The two standards are close, and both are higher than the suspicion needed for a brief investigative stop. Desjardins draws a line on the whiteboard and marks points along it: a hunch, reasonable suspicion, reasonable grounds, and proof beyond a reasonable doubt. A hunch justifies nothing. Reasonable suspicion can justify a brief investigative detention. Only the third point justifies an arrest, and only the fourth justifies a conviction. 'Most of the arguments you will have in court about an arrest are about which side of that third point you were on,' he says.

Limits on the power: when arrest is not needed

Section 495(2) limits the power. For hybrid offences, summary offences and less serious indictable offences, a peace officer shall not arrest without a warrant if the officer believes on reasonable grounds that the public interest can be satisfied without arresting, considering the need to establish the person's identity, to secure or preserve evidence, to prevent the offence from continuing or being repeated or another offence from being committed, and whether the person will attend court. If an officer arrests anyway, the arrest is still treated as lawful for most purposes, but the officer must then consider releasing the person as soon as possible, and the principle of restraint in section 493.1 points the same way.

Reyes confirmed Whitcomb's identity from her driver's licence and a records check. She had no record and no outstanding matters. She apologized, said she had lost her job in January and had been embarrassed to ask for help. Reyes told her she was under arrest for theft, explained her rights and asked a few questions. Then she and Malhotra talked through the decision. The identity question was settled, the evidence was in the basket and on video, nothing suggested the theft would continue, and there was no reason to think Whitcomb would not come to court. Reyes released her on an appearance notice requiring her to attend court and to appear for fingerprinting, and noted that she would recommend Whitcomb for the Crown's pre-charge diversion program. The whole process took 70 minutes, most of it paperwork.

Arrest warrants and entering homes

Arrest on a warrant follows a different path. A justice or judge who issues a warrant has already decided that there are grounds, so an officer executing it needs to confirm that the warrant is valid and in force and that the person in front of them is the person named. Warrants are generally valid throughout Canada once properly endorsed where needed, and officers confirm them through the Canadian Police Information Centre. To enter a home to arrest someone, police generally need judicial authorization under the Feeney warrant provisions in sections 529 to 529.5 of the Criminal Code, which Parliament added after R. v. Feeney in 1997, unless exigent circumstances such as hot pursuit or an imminent risk of harm exist.

Desjardins stresses that the home has special protection in both countries. An arrest in a public place on reasonable grounds may be lawful, while the same arrest made by walking into a person's living room without a warrant or exigent circumstances may not be. Students who go on to patrol will face this distinction often, especially on calls where a suspect has gone home before police arrive.

When an arrest is unlawful

An arrest is unlawful if the officer lacks a statutory or common law power to make it. In R. v. Tim in 2022, the Supreme Court of Canada held that an arrest based on an officer's mistaken belief about the law, in that case a mistaken belief that a prescription drug was a prohibited substance, was arbitrary and breached section 9 of the Charter, and the searches that followed breached section 8. The Court still admitted the evidence under section 24(2) in that case, but the lesson for officers is clear: a mistake of law, however honest, does not supply reasonable grounds. The consequences of an unlawful arrest are serious: evidence may be excluded, the person may sue, and the officer may face discipline.

Any single factor pointing toward holding would call for a closer look: an unconfirmed identity, evidence still at risk, an offence likely to continue, a real risk of not attending court, or a need for care or protection. In the practice case none does, so the conclusion is release at the earliest reasonable opportunity.

The checklist is a teaching aid, not a decision tool. Real decisions require judgment about the facts, and an officer may find reasons to hold that do not fit neatly into a list. But the exercise shows the structure of the decision: when every factor points to release, the law expects release.

Arresting the wrong person

A warrant authorizes the arrest of the person it names, not anyone who looks like them. Officers who arrest on a warrant must take reasonable steps to confirm identity: comparing the name, date of birth and physical description, checking photographs and fingerprints where available, and listening when the person says they are not the one named. Mistaken identity arrests happen most often with common names, people who have had their identity stolen and relatives who share a name. If an officer arrests the wrong person in good faith on a valid warrant, the arrest may still be lawful at first, but once it becomes clear that the person is not the one named, they must be released immediately and the error recorded. Continuing to hold them is not lawful.

Haddad tells the class about a night early in her career when she arrested a man on a warrant for his cousin, who had used his name. He told her calmly in the car that he had been arrested by mistake twice before and showed her a letter from the court confirming it. She called the court's after-hours line, confirmed it, and released him at the curb. 'He thanked me for listening,' she says. 'That told me how rarely it happened.'

Arresting outside your area

Peace officers in Canada generally have authority throughout the province in which they are appointed, and the Criminal Code allows warrants to be executed anywhere in Canada once properly endorsed where required. Officers who make an arrest outside their usual area should notify the local service, which may have information about the person and the location, and must record why and how the arrest was made.