Finders Keepers, Losers Weepers?? OR Return?

When parking my car at my local shopping centre I noticed a brown shopping bag next to the pillar not far from were I parked my car. When I returned to my car (1 hour later) the bag was still there! On closer inspection the bag contained 2 items of clothing (NWT from local designer shop - receipt in bag indicated purchase of over $700 - size too small for me!). In this situation what would you do?