"School personnel can search students' lockers or personal effects based on reasonable suspicion that the students possess contraband that is either illegal or in violation of school policy." Cambron-McCabe, Nelda H., et al. Legal rights of teachers and students. 2nd ed., Boston, Pearson Education, 2009.
Based on various circumstances, it is NLEA's best advice to leave all search and seizure practices to administration within your building. If there is an issue within your classroom, promptly inform administration to carry out proper search and seizure procedures. This includes cell phones! Do NOT under any circumstance accept the responsibility of searching a student's personal effects without knowledge or presence of an administrator.