Three separate groups of robbers have held up merchants at Baltimore's Mondawmin Mall this summer, police said, and a gunman in the latest attack escaped with $100,000 worth of jewelry and watches.

Sunday's theft at Elite Gold & Diamond included 42 gold rings and diamond-encrusted Rolex and Gucci watches. It fit a pattern of other holdups that have predominantly occurred in the middle of the day, and it marked the second time the jewelry store was hit since August.

The crimes are occurring as city officials and investors work to revive Mondawmin — Baltimore's oldest mall — and surrounding neighborhoods. The shopping center underwent a $70 million renovation about two years ago that brought in a long-awaited Target anchor store, which officials had hoped would draw patrons from across the city who otherwise ventured to the suburbs.