GUY RAZ, HOST:
Retailers have more on their minds today than eager shoppers looking for deals. From member station WHYY in Philadelphia, Elizabeth Fiedler reports that stores there, as well in Chicago and Washington, D.C., have been targeted by a new kind of shoplifting.
ELIZABETH FIEDLER, BYLINE: Flash mobs, those gatherings of people based on social media or text messaging who dance or sing in the mall food court, have a new less-wholesome cousin.
JOE LAROCCA: We're seeing what were calling criminal flash mobs, people that get together for the purpose of stealing from stores, which scare our employees, scare customers and cause damage to our locations.
FIEDLER: That's Joseph LaRocca with the National Retail Federation, which is advising its members on how to deal with the mobs. In the Philadelphia area in June, a mob hit a Sears store. Upper Darby, PA, Police Superintendent Michael Chitwood says he's glad no one was hurt.
SUPERINTENDENT MICHAEL CHITWOOD: We received a radio call of a group of males who came into the Sears in excess of 20. They took wristwatches, underwear, various other items, and they were in and out in a matter of minutes. They ran out the door. Police arrived. They arrested approximately 15 males.
FIEDLER: Joseph LaRocca says retailers are increasingly worried.
LAROCCA: In July, we polled retailers across the country, and about one in 10 companies have experienced a criminal flash-mob incident in their stores. About 50 percent or half of the offenders were apprehended, and in most cases, these were juvenile offenders.
FIEDLER: LaRocca says the incidents happen so quickly, there's little time for store employees to react.
LAROCCA: We have asked companies to monitor the Internet, work closely with mall security and law enforcement officials to identify where a possible criminal flash mob could be headed.
FIEDLER: LaRocca says once a group starts stealing merchandise, workers should stand back, take note of what they're stealing, save the videotape and then work closely with law enforcement to track them down. Police Superintendent Michael Chitwood also advises employees not to interfere.
CHITWOOD: Retailers have to call the police right away and do not try and stop individuals who are in there in these groups, let them take the merchandise. Merchandise can be replaced.
FIEDLER: University of Florida research scientist Dr. Read Hayes is the director of the Loss Prevention Research Council. He says the so-called flash robs are still rare, but it's difficult for stores to prevent them.
DR. READ HAYES: Some of the larger chains - two or three at least - are now starting to look at monitoring social media to look for patterns or possible indications, what we call preincident indicators.
FIEDLER: Hayes says there are steps stores can take to prevent the loss of merchandise if something does happen.
HAYES: If you have apparel, you know, you can crisscross the hangers - that way, you can't just grab them and pull them off - try not to locate some of the high-value, low-profit-margin items too close so they can - and they're not in clusters and readily, you know, removable.
FIEDLER: But Hayes says there's not much convenience stores can do because the group that hits a 7-Eleven is looking less for high-value merchandise and more for stories to tell later. He says cameras may help deter criminals and catch them if something does happen. For NPR News, I'm Elizabeth Fiedler in Philadelphia. Transcript provided by NPR, Copyright NPR.