An informant told the Eagan, Minnesota, police that while walking past the window of a ground-floor apartment, he had observed people putting a white powder into bags. Officer Thielen went to the apartment building to investigate. He looked in the window through a gap in the closed blind and observed the bagging operation for several minutes. When two men left the building in a previously identified Cadillac, other police officers stopped the car. While one of the car's doors was open, the officers observed a black zippered pouch and a handgun on the floor of the vehicle. The officers arrested the car's occupants, Carter and Johns. A later search of the vehicle resulted in the discovery of pagers, a scale, and 47 grams of cocaine in plastic baggies. After seizing the car, the officers returned to the apartment and arrested its occupant, Thompson. A search of the apartment (conducted on the basis of a warrant) revealed cocaine residue on the kitchen table and plastic baggies similar to those found in the Cadillac. Officer Thielen identified Carter, Johns, and Thompson as the persons he had observed taking part in the bagging operation. It was later learned that Thompson was the apartment's lessee and that Carter and Johns had come to the apartment for the sole purpose of packaging the cocaine. Carter and Johns had never been to the apartment before and were in the apartment for approximately two and one-half hours at the general time the bagging operation was conducted. In return for the use of the apartment, Carter and Johns had given some of the cocaine to Thompson. Carter and Johns were charged with controlled substance-related crimes. Prior to trial, they moved to suppress all evidence obtained from the apartment and the Cadillac.
They contended that Officer Thielen's observation of them through the apartment window was an unreasonable search in violation of the Fourth Amendment and that all evidence obtained as a result was inadmissible.
Were Carter and Johns entitled to claim the protection of the Fourth Amendment?