In Commonwealth v. Carey, the SJC upheld a search of a student's locker in which school officials discovered a gun, finding that the search was reasonable under all circumstances. The SJC held that eyewitness information and other evidence provided probable cause, which was not altered by the presence of a police officer during the search, since school officials planned the search before contacting the police. The issue of whether a student has an expectation of privacy in a school locker was addressed by the SJC in Commonwealth v. Snyder, in which, based on an overheard conversation, school officials searched a locker and found marijuana. Legal on-campus searches of students or property used by students during the school day refer only to searches initiated and conducted by public school officials, must abide by the school's written policy on storage of contraband in school lockers, are subject to a standard of reasonableness (although this standard remains unclear), and are not subject to full Miranda warnings.