Please Help!! My Child Steals From Everyone, What Should I Do?

How do you react when you have a young child that steals? You’ve talked to him/her several times, told him/her everything that has to be said about the consequences of pilfering.
You do ALL you can to provide his needs and wants.
But he keeps ‘doing it’. How do you help or stop such a child? A reader sent this in.
Hello,

My son steals from me, my husband, my mother, his grandparents, his friends, everybody!! Please, let’s discuss this here because I’m sure I’m not the only mother having this problem.
If it’s not money, it’s things as small as tiny toys and games from neighbors.
Sincerely, it’s gotten so bad I don’t know what to do with him anymore.
My husband and I now have locks on our bedroom door to keep him out.
Problem started when he was 11 and got into boarding school.
He is 13 now. I’ve threatened him that next time he steals, I would have the police involved.
Of course I don’t want to or plan to do that but I don’t know what else to do.