Under what circumstances can a consensual encounter turn into a Terry stop?

A consensual encounter can escalate into a Terry stop when the Special Agent develops a reasonable suspicion that criminal activity is occurring. This is based on the standard set by the Supreme Court in Terry v. Ohio, which allows law enforcement officers to stop and briefly detain a person for investigative purposes if they have specific and articulable facts suggesting that the person is involved in criminal activity.

In the context of a consensual encounter, an individual is free to leave and is not compelled to answer questions. However, if during the encounter, the Special Agent observes behavior or has information that leads them to suspect criminal involvement—such as unusual nervousness, evasiveness, or association with a known criminal—this can transition the interaction from a voluntary encounter to a brief investigatory stop.

This principle reinforces the law enforcement agency's ability to balance public safety with individual rights, allowing agents to take appropriate action when they have a valid reason to believe illegal activity may be afoot. The circumstances surrounding this reasonable suspicion must be based on the agent's training, experience, and the totality of the circumstances at the time of the stop.