Is texting evidence of criminal behavior? That was the issue before a federal judge in U.S. v. Dukins, Dist. Court, ED Tennessee 2012.
In Dukins, the defendants faced counterfeiting charges. One of the issues was a stop and frisk of the defendants by the police. The officer noted, among other factors, that "it was significant that the men appeared to be texting because, in her experience, scammers are often texting someone inside or outside the store who is acting as a lookout during the scam."
To review, police may make a brief, investigatory stop (a Terry stop) if the police have specific, articulable facts that gave rise to a "reasonable suspicion" that the suspect was engaged in criminal activity. Reasonable suspicion is determined in light of the "totality of the circumstances."