I've been very lucky with my 3 boys. They have never stolen from me. And haven't been into any trouble stealing from others either that I know of.
I was taught by my Grandfather so many years ago. He told me that there were 2 things that I was never, ever to do to him. And that was to Lie or Steal from him. And if I did, he made it very plain and simple what the consequences would be....he would use his Leather Strap. He kept it hung on the wall, in full view of me and my siblings...and he was not hesistant to use it whenever we disobeyed.
Now-a-days, that would be child abuse....and basically, I told my boys the same thing. Don't ever Lie or Steal from me!....Consequences will follow. And whenever they have disobeyed or made bad choices, they were grounded...no TV, computer, Ipod, phone,going to bed early, no friends over....even up to a 2 month time, depending on the infraction.
Keeping ur child close by, and following thru with their punishment, having long talks with them. If it were my child, I would make he/her earn my trust back.