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What is the Difference Between Reasonable Suspicion & Probable Cause?

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What is the Difference Between Reasonable Suspicion & Probable Cause?


There are two main legal concepts that the police apply in a criminal investigation to determine whether to detain someone, search and seize evidence, or arrest someone: reasonable suspicion and probable cause. While these concepts are used interchangeable, different circumstances must be met in order to establish each one.

Reasonable Suspicion

Law enforcement officials must first establish reasonable suspicion to conduct an “investigatory” stop. An investigatory stop includes a traffic stop on the road, stopping a person while walking, and frisking or patting someone down for weapons.

In order to make such a stop, there must be certain circumstances or facts evident that a crime is being committed, has been committed, or will be committed. For example, if an officer on the highway witnesses another driver speeding, driving without headlights on at night, or swerving from one lane to another without signally, the officer has reasonable suspicion that the driver is driving while intoxicated (based on the officer’s training and experience).

Probable Cause

During an investigatory stop, the police must then establish probable cause to make an arrest, obtain a warrant, or search and seize evidence from the scene of the alleged crime. The main difference between reasonable suspicion and probable cause is that the standard for probable cause is met if any reasonable person might believe someone is engaged in criminal activity, while the standard for reasonable suspicion is met if any reasonable officer might suspect criminal activity.

Going back to the example above, if an officer notices that the driver smells like alcohol, has bloodshot eyes, or has difficulty moving or responding to questions, then the officer has a probable cause because any reasonable person would believe the driver is under the influence and make a DUI arrest.

Without establishing these two legal concepts, any evidence gathered at the scene is inadmissible at trial, which will likely result in the dismissal of the entire case.

If you or a loved one has been arrested in Reno, contact the Law Offices of Kenneth A. Stover today and request a free initial consultation. Let a former prosecutor with nearly two decades of experience protect your rights and freedom.

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