§ 2.1 REASONABLE SUSPICION
Principle of Law: Before stopping a suspect, the police must have reasonable suspicion of strange or unusual activity, with one exception: roadblocks.
§ 2.1.1 Generally
Terry v. Ohio, 392 U.S. 1, 88 S. Ct. 1868 (1968)
To substantiate a lawful stop and detention, the State must show that at the time of the stop there was reasonable suspicion of the existence of criminal activity.
State v. O'Meara, 198 Ariz. 294, ¶ 7, 9 P.3d 325, 326 (2000)
In deciding whether the police have a particularized and objective basis for suspecting that a person is engaged in criminal activity, the test is totality of the circumstances. It is not an individualized weighing of each factor involved in the stop.
Pennsylvania v. Mimms, 434 U.S. 106, 98 S. Ct. 330 (1977)
An investigatory stop will be deemed reasonable if the officer can demonstrate that it was not arbitrary or harassing in nature.
Pearson v. Arizona Dep't of Transp., 181 Ariz. 235, 889 P.2d 28 (App. Div.1, 1995)
Certified reports are required to state the officer's reasonable grounds to believe the arrested person had been driving or was in actual physical control of a motor vehicle within this state while under the influence of intoxicating liquor or drugs. This report need not list all reasonable grounds. "Reasonable grounds" are facts and circumstances which would warrant the same belief in a prudent person.
Devlin v. Browning in and for County of Pima, 249 Ariz. 143, 467 P.3d 268 (App. Div. 2, 2020)
There was reasonable suspicion to conduct a DUI investigation based upon a totality of the circumstances. Individualized potentially innocent explanations do not obviate the totality of the circumstances giving rise to reasonable suspicion.
§ 2.1.2 Pretext Stop
Whren v. United States, 517 U.S. 806, 116 S. Ct. 1769 (1996)
The constitutional reasonableness of traffic stops does not depend on the actual motivations of the officers involved. The officer's motivations for stopping a suspect are irrelevant, as long as the officer had an objective basis for the stop. Therefore, there is no such thing as a "pretext stop."
State v. Sprietz, 190 Ariz. 129, 945 P.2d 1260 (1997)
Federal and Arizona case law allow police to use valid, preexisting traffic warrants to effect an arrest, even if the arrest is made to investigate other suspected crimes.
§ 2.1.3 Citizen Informants
State v. Lawson, 144 Ariz. 547, 698 P.2d 1266 (1985)
When an ordinary citizen volunteers information that he or she has come upon in the ordinary course of his or her affairs, completely free from any possible gain from furnishing the information, reliability is enhanced.
Pharo v. Tucson City Court, 167 Ariz. 571, 810 P.2d 569 (App. Div. 2, 1990)
When citizen informants observe a suspect commit a traffic violation, officers need not observe bad driving to have reasonable suspicion to stop the vehicle.
State v. Diffenderfer, 120 Ariz. 404, 586 P.2d 653 (App. Div. 2, 1978)
Information from a citizen who voluntarily comes forward to aid law enforcement is presumed reliable.
§ 2.1.4 Anonymous Citizen Tips
Principle of Law: An anonymous tip requires corroboration before it can be used as grounds for a stop. (Note that once an officer observes a traffic violation, the officer has independent reasons to justify the stop).
Florida v. J.L., 529 U.S. 266, 120 S. Ct. 1375 (2000)
Unlike a tip from a known informant whose reputation can be assessed and who can be held responsible if the allegations turn out to be fabricated, an anonymous tip must be corroborated by a moderate indicia of reliability.
State v. Altieri, 191 Ariz. 1, 951 P.2d 866 (1997)
Although an anonymous tip may, in some circumstances, be sufficient to support a stop, the tip must show sufficiently detailed circumstances to indicate that the informant came by his or her information in a reliable way. If the tip itself fails to provide sufficient underlying circumstances demonstrating the reliability of the information, the...
