I think the OP did the right thing. I doubt he'll do anything similar or show his face in the communal areas of the house more than necessary because he surely knows that he got a lucky break.
Of the few incidences of friends stealing from friends during my time at uni, the only 2 i remember are a girl who stole £1000s from her flatmates bank accounts and left uni in disgrace although I don't think the police became involved and a girl who was selling her flatmates' clothes on ebay, whose flatmates had to do exactly what the OP has chosen to do. Getting caught stealing from ppl you know or live with tends not to get you locked up but it does come with its own innate punishment of the social disgrace that goes along with it.