Bailey v. United States, 514 U.S 137 (1995) is one of the cases that mostly used as reference case in federal criminal code, especially in reference to use of firearms and police search. This case lead the Congress to amend statute 18 U.S.C. s 924 to include possession of firearms as a crime requiring mandatory term of five-year imprisonment. In addition, this case raised serious questions on rights granted under 4th Amendments on police search and seizure. In view of the provisions of Fourth Amendment and based on previous court rulings, law enforcement officers have the power to detain a person in pursuit of implementing search warrant if the person has left the building to be searched immediately before the search begins.