The dramatic video footage appears on TV news and social media: A large group of people storm into a store, smashing display cases and snatching loose merchandise before escaping in minutes before the police have time to respond, NPR reports. Authorities say these so-called "flash mob" thefts are sometimes organized on social media and often target high-end goods that can be resold. The thieves occasionally use violence to carry out their crimes and aren't hampered by traditional techniques to prevent shoplifting, such as security tags and alarms. California has seen a number of large-scale smash-and-grabs in recent months. Last month in Philadelphia, thieves looted stores across the city over the course of several nights, with prosecutors charging more than 70 people.
It's unclear from the data whether these kinds of incidents actually are on the rise. Still, retailers, law enforcement authorities and elected officials are raising the alarm about a trend they say is worsening. "First and foremost, these are very traumatic events. They also have the biggest potential for violence," said David Johnston of the National Retail Federation. "The disruption to the consumer and the disruption to the retailer is [also] much greater, because the store has to close, the store has to repair, merchandise has to be replenished," he added. People steal goods from stores in a number of ways, from simple shoplifting to organized retail crime, in which coordinated groups boost merchandise to resell on the black market. Another category — "flash mob" thefts or smash-and-grabs — can prove especially tricky to stop.