Reasonable Grounds to Suspect and Reasonable Grounds to Believe

• Author: Brian H. Greenspan, Vincenzo Rondinelli
• Profession: General Editors
• Pages: 249-299

249

Reasonable

Grounds to

Suspect and

Reasonable

Grounds to Believe

8

I. Introduction ............................................. 

A. Overview of Reasonable Grounds to Suspect ............. 

B. Overview of Reasonable Grounds to Believe .............. 

II. What Must the Ocer Suspect or Believe? .................... 

A. Detention Powers: What Must the Ocer Suspect? ........ 

B. Arrest Powers: What Must the Ocer Believe? ............ 

III. Dening the Standards .................................... 

A. Dening Reasonable Suspicion ........................ 

B. Dening Reasonable Belief ............................ 

IV. Were the Grounds Sucient? ............................... 

A. Sucient Factors Standing Alone ....................... 

B. Relevant Factors Generally ............................ 

C. Relevant Factors for Drug Oences . . . . . . . . . . . . . . . . . . . . . 

D. Relevant Factors for Firearms Oences .................. 

E. Relevant Factors for Impaired Driving Oences ........... 

F. Never Relevant Factors ............................... 

G. Proling ........................................... 

V. The Approach to Analyzing Grounds ......................... 

A. Standard of Review .................................. 

B. Subjective and Objective Grounds ...................... 

C. Common Sense, Flexibility, and Practicality ............... 

D. Police Training and Experience ......................... 

E. Exculpatory Information .............................. 

F. Hearsay ........................................... 

G. Incorrect Information and Mistake ..................... 

H. Involuntary Information .............................. 

I. Information Obtained Through Charter Violations ......... 

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250Detention, Arrest, and the Right to Counsel

I. Introduction

Subject to a reasonable and justif‌iable limit under section 1 of the Canadian Charter

of Rights and Freedoms,1 section 9 requires police ocers to have grounds to lawfully

invoke their powers of detention and arrest. Having grounds means that the ocer

can articulate the facts or inferences that warrant an interference with a person’s lib-

erty. While police powers to detain and arrest provide the community with valuable

protection, allowing ocers to routinely exercise these powers without any grounds

would subject the public to disproportionate and indiscriminate interference with

their liberty.2 When it comes to detention powers, the ocer’s grounds must nor-

mally meet the “reasonable suspicion” standard. Various statutory and common law

detention powers are premised on this standard. When it comes to arrest powers,

including the statutory power to arrest without a warrant, the ocer’s grounds must

meet the higher “reasonable belief” standard, which is also described in the jurispru-

dence as “reasonable and probable grounds.”3

Reasonable grounds to suspect and reasonable grounds to believe both contain

subjective and objective components. The ocer must form a subjectively held sus-

picion or belief that must also be objectively reasonable. To permit a reviewing court

to adjudicate the constitutional validity of the suspicion or belief, the ocer must be

able to articulate the information that grounded their state of mind. The requirement

for an ocer to disclose their grounds in the context of a Charter application is criti-

cal to the process of rigorous judicial scrutiny.4 Since both detentions and warrantless

arrests occur without judicial pre-authorization, it is only through an after-the-fact

analysis that individuals are protected against arbitrary state action. This review pro-

cess can shed light on whether the ocer’s decision to detain or arrest a person was

constitutionally inf‌irm, such as where it was premised on stereotypical reasoning.5

A. Overview of Reasonable Grounds to Suspect

The reasonable grounds to suspect standard has appeared in Canadian legislation for

many years. For example, the 1960s version of Ontario’s Liquor Licence Act6 enabled

1 Part I of the Constitution Act, 1982, being Schedule B to the Canada Act 1982 (UK), 1982, c11

[the Charter].

2 Dumbell v Roberts, [1944] 1 All ER 326 at 329 (CA).

3 See R v Zacharias, infra note 353 at paras 26-29; R v Tim, infra note 244 at paras 24, 25.

4 Challenges to the suciency or propriety of an ocer’s grounds can occur in the context of an

application under s 8 or 9 of the Charter. Counsel will argue s 8 when the grounds were neces-

sary for a search and s 9 when the grounds were necessary for a detention or arrest. Counsel

will bring an application under both sections when a detention or arrest led to a search or when

a lawful detention or arrest was a prerequisite to the search.

5 R v Ahmad, 2020 SCC 11 at para 25.

6 RSO 1960, c 218.

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Chapter  Reasonable Grounds to Suspect and Reasonable Grounds to Believe 251

licence holders to expel a person from a premises upon reasonable grounds to suspect

that the person was committing an oence under the Act.7 English law has also long

recognized police powers premised on a reasonable suspicion, including the power

of arrest. Early English decisions def‌ined “suspicion” as a “state of conjecture or

surmise where proof is lacking.”8

But to understand how Canadian courts have def‌ined reasonable suspicion, the

story must begin in the American jurisprudence. The equivalent American standard

is known as an “articulable cause,” which the United States Supreme Court has set

as the standard to stop and search a suspect. To justify the intrusion, “the police

ocer must be able to point to specif‌ic and articulable facts which, taken together

with rational inferences from those facts, reasonably warrant that intrusion.”9 The

Court developed this standard to ensure that the courts could scrutinize the con-

duct of those responsible for enforcing the law. “Anything less would invite intru-

sions upon constitutionally guaranteed rights based on nothing more substantial than

inarticulate hunches, a result this Court has consistently refused to sanction.”10 The

Court later developed the def‌inition of “articulable cause” to require the detaining

ocer to have “a particularized and objective basis for suspecting the particular per-

son stopped of criminal activity” based on “the totality of the circumstances” or “the

whole picture.”11

Canadian courts imported articulable cause into Canada and eventually renamed

it “reasonable suspicion” or “reasonable grounds to suspect.”12 Although the courts

over time have ref‌ined the analysis of an ocer’s suspicion, the fundamental prin-

ciples have stayed the same. Therefore, older Canadian jurisprudence on articu-

lable cause remains good law on what it means for an ocer to hold a reasonable

suspicion.13

Reasonable suspicion requires an ocer to base their decision to detain a person

on objectively discernable facts. Since the detention will occur without any judicial

pre-authorization, it is important that ocers learn and appreciate how the standard

operates to govern their conduct. When the standard is respected, it helps to prevent

the indiscriminate and prejudicial exercise of police power. 14 Even though the grounds

7 Liquor Licence Act, s 53(6).

8 Police and Criminal Evidence Act 1984 (UK), c 60, s 24; Hussien v Kam, [1969] 3 All ER 1626

at1630.

9 Terry v Ohio, 392 US 1 (1968) at 20, 21.

10Ibid.

11US v Cortez, 449 US 411 (1981) at 417, 418.

12R v Mann, 2004 SCC 52 at para 30.

13See e.g. the treatment of R v Simpson, 1993 CanLII 3379 (ONCA) in R vKang-Brown, 2008

SCC 18 at para 76.

14 See R v Chehil, infra note 80 at para 3.

© 2025 Emond Montgomery Publications. All Rights Reserved.