Sam was on a Greyhound bus that pulled into a rest stop. After all of the passengers had exited the bus to buy refreshments, stretch their legs, and do other things, Officer Green boarded the bus with Buff, a trained drug detection dog, and performed a drug sweep. The sweep consisted of removing all bags located in overhead compartments, placing them on the seat below, and having Buff sniff them. Buff alerted to a maroon bag. Green put all the bags back in the overhead compartments before the passengers returned to the bus and, after they reboarded, inquired whether any of them owned a maroon bag. When no one claimed the maroon bag, Officer Green removed it from the bus, opened it, and examined the contents.

On discovering 24 grams of crack cocaine, along with a driver's license with Sam's picture on it, he reboarded the bus and arrested Sam. At his trial for possession of cocaine, Sam moved to suppress the evidence on the grounds that it was obtained through an illegal search and seizure.

The purpose of this exercise is to determine whether Officer Green performed any act that the Fourth Amendment treats either as a search or a seizure.

Question :

(1) Did Officer Green's removal of Sam's bag from the overhead compartment and putting it on the seat below constitute a seizure within the meaning of the Fourth Amendment?

(2) Did exposing Sam's bag to an examination by Buff constitute a search?

(3) Did Officer Green's removal of Sam's bag from the bus when no one claimed it constitute a seizure?

(4) Did Officer Green's subsequent opening of Sam's bag and examining the contents constitute a search?