A shooting in a busy mall in Laurel, Maryland, during Memorial Day’s weekend that left two people injured — one of them, a passer-by — occurred during a transaction in an online market, according to police. Local internet sales through sites like Facebook Marketplace, OfferUp and Craigslist are increasing as more people try to stretch money by buying second-hand items. The shooting took place around noon Sunday, next to the Harris Teeter grocery…