Investigative detention in practice

Desjardins plays body-worn camera footage from a Port Ardent stop, with faces blurred. An officer pulls up beside a young man walking quickly away from a convenience store that had just been robbed. The officer gets out, says 'Hold on a second, I need to talk to you,' explains that the store was just robbed by a man in a grey jacket, and asks the young man where he is coming from. The young man is wearing a grey jacket. Two minutes later, the store clerk arrives in another cruiser, looks at him and says it is not the man. The officer thanks the young man, explains why he was stopped, gives him a card and lets him go. The whole encounter takes four minutes. 'That,' Desjardins says, 'is investigative detention done properly. Brief, focused, explained, and ended as soon as the reason for it disappeared.'

LES-111 covered the constitutional framework for detention: when a person is detained, the standards for stops and arrests, and the leading cases. This lesson is about doing it: the practical steps, the limits on scope and duration, protective searches, vehicle stops, and the records that let a supervisor and a court see what happened.

The legal basis in brief

Investigative detention is a common law power recognized in R. v. Mann (2004) under the Waterfield test. An officer may detain a person for investigative purposes if there are reasonable grounds to suspect, in all the circumstances, that the individual is connected to a particular crime and that the detention is reasonably necessary on an objective view of the totality of the circumstances. The person must be told promptly why they are detained under section 10(a), and, as R. v. Suberu (2009) held, informed of the right to counsel immediately on detention, subject only to safety concerns. The person is not obliged to answer questions. The detention must be brief, and the officer may conduct a protective pat-down only where they believe on reasonable grounds that their safety or the safety of others is at risk.

Starting a detention well

Most of what goes wrong in a detention goes wrong in the first thirty seconds. An officer who approaches with a hand on their holster and a demand for identification creates a detention immediately, whether or not they have grounds for one. An officer who wants only to ask questions should say so and make clear that the person may leave. When an officer does have grounds, the best practice is to say three things at once: who you are, that the person is being detained, and why. 'I'm Constable Patel with Port Ardent police. I need you to stop for a few minutes. A store was just broken into two blocks from here, and you match the description of the person we're looking for.' That single sentence satisfies section 10(a), sets the scope, and starts the clock. The right to counsel should follow immediately, unless there is a safety reason to secure the situation first.

Desjardins asks the class to imagine being on the other side of that encounter. Linh Tran says her cousin Bao was never told why he was stopped, and assumed it was because of how he looked. Jesse Morningstar says people in his community often assume the worst when an officer does not explain. Both say that an explanation, even a brief one, would have changed how the stop felt. Desjardins agrees and adds that it changes how a court sees it too: an officer who explained the reason at the start has made a clear record of the grounds they relied on.

Scope: what a detention allows

A detention allows the officer to hold the person briefly while they investigate the suspicion that justified it: to ask questions, to check identification if the person offers it or the law requires it, to bring a witness for a quick identification, or to make database checks. It does not allow a general search for evidence, a search of a bag or pockets beyond a protective pat-down, a trip to the station, or questioning about unrelated matters as a fishing expedition. If the person declines to answer, the officer must work with what they have; refusing to answer is not itself grounds for arrest.

Moving a detained person is a sensitive question. Placing someone in the back of a cruiser for a short time, for instance in bad weather or for safety, may be reasonable, but it increases the restraint and must be justified. Transporting a detained person to the station or to the scene generally turns a detention into something closer to an arrest and needs separate justification.

Handcuffing during a detention is another hard question. Handcuffs are not automatically an arrest, but they are a significant restraint that must be justified by a real safety concern, such as reasonable grounds to believe the person is armed, a struggle, or a high-risk situation like a robbery with a weapon. Officers who handcuff routinely during detentions invite findings that the detention became arbitrary or unreasonable. The decision should be recorded with the reasons, and the handcuffs removed as soon as the safety concern passes.

Protective searches during a detention

Mann limits the protective search to a pat-down of the person's outer clothing for weapons, where the officer reasonably believes that their safety or that of others is at risk. It is not a search for evidence. In Mann itself, the officer felt something soft in the young man's pocket, reached in, and found marijuana; the Supreme Court excluded the evidence because a soft object posed no safety risk, so reaching in exceeded the protective purpose. In R. v. MacDonald (2014), the Court held that a safety search must be based on reasonable grounds to believe there is an imminent threat to safety and must be reasonably necessary.

Desjardins demonstrates a pat-down on a training dummy, explaining each movement: hands on the outside of clothing, flat palms, starting at the areas where weapons are most often carried, never reaching into pockets unless a hard object that could be a weapon is felt. He tells the class that their notes must explain both why they believed a pat-down was needed and what they felt that justified going further, because a court will examine both.

Duration: keeping detentions brief

The law does not set a fixed time limit on a detention, but every court that has looked at the question has said the same thing: the detention must last no longer than needed to confirm or dispel the suspicion, and the officer must pursue the investigation diligently. Delays that come from the officer's own choices, such as waiting for a dog that has not been called or running unrelated checks, count against the reasonableness of the detention. Haddad's quarterly review of investigative detentions in Port Ardent records how long each lasted and whether new grounds arose during it, which can justify a longer detention.

# 200 Port Ardent investigative detentions in one quarter, by duration
bands = ["under 10 min", "10 to 20 min", "20 to 30 min", "over 30 min"]
detentions = [118, 52, 19, 11]
new_grounds = [0, 6, 9, 8]      # detentions where new grounds were recorded during the stop
total = sum(detentions)
for b, d, g in zip(bands, detentions, new_grounds):
    print(f"{b:13} {d:4}  {d / total:.2f}  new grounds recorded: {g}")
long_ = detentions[2] + detentions[3]
long_with = new_grounds[2] + new_grounds[3]
print("over 20 minutes:", long_, "with new grounds:", long_with, "without:", long_ - long_with)

under 10 min   118  0.59  new grounds recorded: 0
10 to 20 min    52  0.26  new grounds recorded: 6
20 to 30 min    19  0.10  new grounds recorded: 9
over 30 min     11  0.06  new grounds recorded: 8
over 20 minutes: 30 with new grounds: 17 without: 13

Most detentions were short: 170 of 200 lasted under twenty minutes. Of the 30 that lasted longer, 17 had new grounds recorded, such as a witness identifying the person or contraband found in plain view, which can justify a longer detention or an arrest. The other 13 are the ones Haddad reviews in detail, because each is a detention that went on with no recorded reason. Some will turn out to have good explanations that were not written down. Others will be coaching conversations.

Vehicle stops

Vehicle stops are the most common police contact. Section 216 of Ontario's Highway Traffic Act allows an officer, in the lawful execution of their duties, to require the driver of a motor vehicle to stop. In R. v. Ladouceur (1990), the Supreme Court upheld random roadside stops to check licences, insurance, mechanical fitness and sobriety, even though they are arbitrary detentions under section 9, as reasonable limits under section 1. But the stop must be used for those purposes. In R. v. Nolet (2010), the Court accepted that a stop for a highway purpose can evolve into a criminal investigation when new grounds arise, but it cannot be a pretext for a search without grounds. Passengers are detained only if the circumstances show it, though drivers are always detained.

Desjardins tells the class that vehicle stops carry particular risks of bias, because officers have a lot of discretion about which cars to stop. Port Ardent records the reason for every stop, the outcome, and the officer's perception of the driver's race, and publishes the summary each year. The data are not perfect, but they let the service and the public see whether stops fall more heavily on some groups than the driving population would explain, and they have led to changes in how officers choose which minor violations to enforce.

Ending a detention and recording it

A detention ends in one of three ways: the suspicion is dispelled and the person is released; new grounds arise and the person is arrested; or the officer decides the matter is better handled another way, such as a summons or a referral. In each case, the officer should tell the person clearly that the detention is over. Port Ardent officers give every detained person a card with the officer's name and badge number, the incident number, and a summary of the reason for the stop, a practice the service adopted in 2018 and that meets the requirements of Ontario's regulation on the collection of identifying information in certain circumstances where it applies. The detention record should show the time it started, the grounds, any protective search and why, any new grounds, and the time and manner it ended.