I have had this experience with my son as well. All 3 of my girls have never displayed this behavior. I read what I could to investigate what to do and found some of the advise helpful. One thing that helped me was that this is common with boys in this age group and not to overreact or shame them with questions that make them feel bad about themselves like "what is wrong with you?" They need to know it's wrong and feel remorse but not shame. The best thing to do is to react calmly and with love explaining why stealing is harmful to society and that stealing from family causes a break down in trust and respect. Have him own up! Give him appropriate punishment (losing some priviledge for a specified time, paying back 7X the amount stolen-which is what scripture demands of a thief) That is if they receive an allowance! Which is also important so they have autonomy with their own money. When kids have no spending money of their own they are tempted to take it from mom if they can. Somehow they think we are their personal piggy banks LOL!At least my girls ask first. Also, have a heart to heart and try to find out what is motivating him to take stuff. My son used to take money to give away at school trying to make friends and hoping he would be liked. Very Sad when I figured that out as he is often rejected being the new kid. We move often due to hubby's job situation. Anyway, hope that helps!