What is the scope and duration of a police stop?

Here, the questions asked by the police officers were reasonably related in scope to the justification for the stop. Follow-up questions were made necessary by defendants' unconvincing and suspicious answers to the initial, routine questions. See United States v. Richards, 500 F.2d at 1029. Even if we accept defendants' claim that the separate questioning lasted 10-12 minutes, there is nothing in the record to suggest that the stop was for a longer period than was reasonably necessary. Thus, we cannot find that either the scope of the inquiry or the duration of the investigative stop was excessive.