My sister is a theif.

My sister is 17. She isn't pregnant and is on birth control. She has been stealing my prenatal and granola bars. I set up my Web cam and watched her enter my room and take these things! I can only handle the gummie prenatals and she acts like they're candy! The only way I can take them is to eat a granola bar wait 5 or 10 minutes then take my prenatals. ...I don't know how to go about dealing with this. There IS a lock on the door and I do use it she picks it.