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9.19 Particular Rights—Fourth Amendment—Unreasonable Seizure of Person—Exception to Warrant Requirement—Terry Stop

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In general, a seizure of a person for an investigatory stop is reasonable if, under all of the circumstances known to the officer[s] at the time:

1. the officer[s] had a reasonable suspicion that the person seized was engaged in [criminal activity] [other conduct justifying investigation, i.e., a traffic infraction]; and

2. the length and scope of the seizure was reasonable.

In order to prove the seizure in this case was unreasonable, the plaintiff must prove by a preponderance of the evidence that the officer[s] lacked reasonable suspicion to stop [him] [her] or that the length and scope of the stop was excessive.

"Reasonable suspicion" is an objectively reasonable belief based on specific and articulable facts.

In determining whether the length and scope of the seizure was reasonable, consider how the officer[s] restricted the plaintiff’s liberty and the officer’s reason[s] for using such methods and for the length of the stop.


Use this instruction only in conjunction with the applicable elements instructions, Instruction 9.2–9.7, and in conjunction with Instruction 9.18 (Particular Rights—Fourth Amendment—Unreasonable Seizure of Person—Generally).

A police officer may conduct a brief stop for investigatory purposes when the officer has only "reasonable suspicion" to believe the stopped individual is engaged in criminal activity. See Terry v. Ohio, 392 U.S. 1, 23-27 (1968). See also Allen v. City of Portland, 73 F.3d 232, 235 (9th Cir.1996). Moreover, an investigatory stop of a vehicle is justified under the Fourth Amendment if the officer reasonably suspects that only a traffic violation has occurred. United States v. Miranda-Guerena, 445 F.3d 1233, 1236 (9th Cir.2006).

"Reasonable suspicion is formed by ‘specific, articulable facts which, together with objective and reasonable inferences, form the basis for suspecting that the particular person detained is engaged incriminal activity.’" United States v. Dorais, 241 F.3d 1124, 1130 (9th Cir.2001) (quoting United States v. Michael R., 90 F.3d 340, 346 (9th Cir.1996)). It requires only "a minimal level of objective justification." Illinois v. Wardlow, 528 U.S. 119, 123 (2000). A court must consider the totality of the circumstances when determining whether reasonable suspicion existed. United States v. Osborn, 203 F.3d 1176, 1181 (9th Cir.2000).

"There is no bright-line rule to determine when an investigatory stop becomes an arrest." Washington v. Lambert, 98 F.3d 1181, 1185 (9th Cir.1996) (citing United States v. Parr, 843 F.2d 1228, 1231 (9th Cir.1988). The analysis depends upon the "totality of the circumstances" and is "fact-specific." Washington, 98 F.3d at 1185.

In looking at the totality of the circumstances, we consider both the intrusiveness of the stop, i.e., the aggressiveness of the police methods and how much the plaintiff’s liberty was restricted, . . . and the justification for the use of such tactics, i.e., whether the officer had sufficient basis to fear for his safety to warrant the intrusiveness of the action taken. . . . In short, we decide whether the police action constitutes a Terry stop or an arrest by evaluating not only how intrusive the stop was, but also whether the methods used were reasonable given the specific circumstances. . . . As a result, we have held that while certain police actions constitute an arrest in certain circumstances, e.g., where the "suspects" are cooperative, those same actions may not constitute an arrest where the suspect is uncooperative or the police have specific reasons to believe that a serious threat to the safety of the officers exists. "The relevant inquiry is always one of reasonableness under the circumstances.". . .

Id. (citations omitted).