What must an officer demonstrate to justify a stop and frisk?

To justify a stop and frisk, an officer must demonstrate reasonable suspicion that a person is involved in criminal activity and that they may be armed and dangerous. This concept stems from the need to balance individual rights with public safety. Reasonable suspicion is a lower standard than probable cause, allowing officers to act on specific and articulable facts rather than just a hunch or vague suspicion.

In practice, this means that if an officer observes behavior that suggests criminal activity and poses a potential threat to safety, they are justified in stopping the individual for questioning and, if necessary, conducting a frisk for weapons. This principle is established in the Supreme Court case Terry v. Ohio, which affirms that officers can take preventive steps to protect themselves and the public based on reasonable suspicion of danger.

Other alternatives, such as knowledge of a person's criminal history, while potentially relevant in assessing a situation, do not in themselves justify a stop and frisk. Simply having clear evidence of an ongoing crime is more closely related to probable cause, which is not required for a stop and frisk. Similarly, a report from other officers may provide context but does not replace the need for the observing officer to form their own reasonable suspicion based on the situation at hand.