Section 1983 unreasonable detention claim
At trial, to prove that an officer unreasonably detained a person, that person must show, more likely than not, that the officer either:
(1) lacked reasonable suspicion to stop the person; or
(2) that the length or scope of the stop was excessive.
Ninth Cir. Civ. Jury Instr. No. 9.21
To prove that the officer lacked reasonable suspicion, and to hold the officer liable, a person must prove either of two negatives. One way to officer liability is by showing that no “particularized and objective basis” existed for the officer to have suspected that the person was involved in criminal activity. Ninth Cir. Civ. Jury Instr. No. 9.21. As discussed above, “particularized” refers to facts specific to that person; for example, reasonable suspicion generally cannot exist based on a person’s merely standing near others suspected of criminal activity.
In assessing reasonable suspicion, officers are allowed to draw upon their own experience and specialized training to make inferences from, and deductions about, all of the facts that the particular encounter presents them with. Ninth Cir. Civ. Jury Instr. No. 9.21. Therefore, they may cite their “training and experience” to add more “facts” to the group of facts leading to reasonable suspicion. But an officer may not base reasonable suspicion on particularized facts to the person to be detained.
The second way to officer liability involves proving that the length or scope of the stop was excessive, making it an unreasonable seizure. Through intrusive police actions, an otherwise reasonable detention supported by reasonable suspicion may turn into an unreasonable arrest lacking probable cause. At trial, the judge will instruct the jury to consider all of the circumstances of the incident, including:
(1) the intrusiveness of the stop, such as the methods the police used, the restriction on the plaintiff’s liberty, and the length of the stop;
(2) whether the methods used were reasonable under the circumstances; and
(3) other factors applicable to the particular case.
Ninth Cir. Civ. Jury Instr. No. 9.21
Generally, to prevail at trial, a person will need to show the jury that the officer’s use of force or other coercion made the detention unreasonable.