The police have a reasonable suspicion that a traveler is carrying contraband and ask the traveler at the airport if they can search his luggage. the traveler refuses. the officers lack probable cause and tell the traveler he is free to go. however, they refuse to return the luggage to the traveler, telling him they are waiting for a drug-detection dog. the traveler waits for two hours, but the dog does not appear. although lacking probable cause, the police still refuse to give the traveler the luggage, and he leaves. under the fourth amendment, this police action is: