Calm down.
You seem to think he'll end up in Holloway because he helped himself to a sweet three years ago, and also a computergame. He won't, and you going off on one, threatning to shop him in to the authorities now won't help the situation.
For sure you are upset and you fear for him, but you need to examine why stealing is so black and white with such terrible hell in a handbasket, one track consequences?
He seems very bright, and you're very lucky to have a bright DS.
He also sounds bored, and like he's becoming addicted(?) to whatever games he's playing. Is he slightly obsessive about them?
You need to have more family chats. You need to be honest and also to stop thinking about punishment and more about discipline. You are the authority, not some guy in a uniform, or some big guy in the sky, for that matter.
He sounds like he'll do very well in the city!
Threatening him with the big bad bogeyman policeman will make you look rather foolish. He may need the police's help in his life, we all do at some time. are you willing to make him distrustful of them, and worse still, of you?
Be honest, and talk with him. Why did he think he was entitled? Why did he try and cover up his tracks, did he know it was wrong? why did he go ahead, didnt he care that you were paying?
does he not understand that everything is found out sooner or later, that nothing is ever a secret.
LISTER VERY CAREFULLY TO HIS ANSWERS and don't interrupt