You should give them the warning first and if they continue this process complain it to u r respective classteacher
plss send the answer of that question also which I posted erlowr then that quess
1. Take the witness and discuss the matter with your class teacher. 2. You should discuss the matter with the subject teacher who was incharge of that particular period. 3. Your class teacher will ask for the theft and she will give a time period to come and give the thing to her. 4. If the theft don't come out within the warning time given then you can take permission of your classteacher and check bags of your classmates. 5. After coming infear the theft will automatically return your things............yeah! You caught the thief!