This is simply wrong. Individuals subject to routine traffic stops or customs inspections, circumstances which are not custodial, are rarely free to leave while being questioned by an officer. The relevant inquiry, however, as stated above, is whether there was an arrest or restraint on freedom of movement of the degree associated with a formal arrest. A custody determination requires inquiry into all circumstances surrounding the interrogation. Finally, we note that the court, relying on outmoded circuit opinions, discussed certain factors, such as whether there was probable cause to make an arrest and the officers' focus on the defendants, which are not relevant to a Miranda inquiry.
Defendants argue that the court's test, taken as a whole, is consistent with our precedent.
Although there may be tests which, though formulated differently, approximate the proper standard, this is not one of them. Accordingly, we remand this case to the district court for application of the correct legal test. On remand, the court may take additional evidence on the relevant factual issues. The order suppressing evidence is vacated. We remand to the district court for proceedings consistent with this opinion.