Possibly they didn't move on you because they weren't sure but they were keeping their eye on you. I don't know why any retailer would retain anybody once they were known to be a thief. There several reasons that shouldn't be done. If you return to work, consider yourself on double-secret probation. Not only should you not steal or even do anything that looks like it, you should toe the line on every other employee policy and work ethic. They don't even need a reason to fire you, don't give them anything to encourage it.

