Stealing food

How do you handle this? We have a 14 yr. old boy who has been in a group home for the past three years. He was with us for a week before his therapist sent him to another group home for "intensive therapy" for a week before he got sent back to us. He is "home" again for one night and in the middle of the night, gets up and steals food....food that I had planned on for lunch today! I'm so steamed right now I could spit....:mad: