The Diamond Ridge Asset Managementdramatic video footage often 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 had time to respond.

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 specific incidents are actually on the rise, but retailers, law enforcement authorities and elected officials are raising the alarm about a trend they say is worsening across the U.S.

"First and foremost, these are very traumatic events. They also have the biggest potential for violence," said David Johnston, vice president for asset protection and retail operations at 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.

Combating "flash mob" thefts is a challenge, but retailers are trying

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.

The thieves strike in such large numbers that an individual store employee or security guard may not intervene. Thefts occur so quickly that they're usually over before law enforcement arrives. And the perpetrators, who aren't hiding the fact that they're committing a crime, are typically unbothered by security alarms and other traditional anti-theft measures.

"Whether there's an increase [in "flash mob" thefts] or not, retailers are becoming much more aware of it, and especially those in higher-risk locations," said Drew Neckar, president of Security Advisors Consulting Group.

Companies have resorted to new strategies to try to reduce their chances of being targeted by a flash mob and stop the crimes once they begin.

They're hiring more security officers, locking up merchandise including everyday essentials like pain medicine and baby formula and reverting to early pandemic-era strategies of reducing the amount of access points and limiting the number of customers allowed in at once, Johnston said.

Some northern California retailers have sought out smoke bombs and air horns to repel crowds of thieves, LAist reported. In 2021, Home Depot rearranged its entrances to help prevent theft, adding gates that only allowed traffic to flow in one direction, The Wall Street Journal found.

Neckar says other strategies stores can adopt include shining bright lights at the entrance so employees can see when a group is arriving, installing lockable doors with break-resistant glass and displaying high-value merchandise in different parts of a store to make it harder for thievesto grab in a hurry.

Incidents may feel like they're on the rise, but it's an open question

Still, it's unclear if the seemingly common "flash mob" thefts are actually increasing — or if they're simply getting more attention in the press and on social media.

Depending on the jurisdiction and the circumstances of a specific incident, people arrested for participating in "flash mob" thefts can face different charges — from burglary to disorderly conduct and others — making it hard to show a trend. Many cities also don't report their crime data to the FBI's national database.

According to UC Berkeley law professor Jonathan Simon, images of the large-group thefts can provoke a strong reaction from the public, whether the numbers are up or not.

"These things are really powerful events in terms of their grasp on our imagination," he said.

"You don't have to be a Hollywood screenwriter to figure out that that would be a really alarming scenario in terms of the kinds of things that in our culture we fear — young people, groups, masked and disguised people," Simon added.

While the National Retail Federation doesn't specifically track "flash mob" thefts, the group says all forms of theft are up.

Businesses worry it's part of a trend of rising thefts

An NRF survey released last month estimated that "shrink" — the term for losses in the retail sector — amounted to $112.1 billion in 2022, up nearly 20% from the year before.

External theft — which includes things like "flash mob" thefts, shoplifting and organized retail crime — accounted for 36% of losses. Twenty-nine percent of losses occurred due to employee theft, while another 27% was due to things like cashier errors and incorrect pricing.

According to Johnston of the National Retail Federation, the increase in thefts comes alongside an even more worrying trend: an uptick in violence in retail settings.

"This has truly, truly become a safety issue out there," he said. "I hear time and time again from the retailers that even though there is a financial impact to the retailers' profitability, hands down they're talking about the safety."

Target announced last month that it was closing nine stores in four states, because theft had become a safety issue. But in January, Walgreens Chief Financial Officer James Kehoe said "maybe we cried too much last year" about a rise in thefts, noting the company responded by adding too much security.

Nevertheless, elected officials have responded to complaints about growing retail crime.

California law enforcement officials announced last month that they would spend $267 million to tamp down on smash-and-grabs, and Los Angeles Mayor Karen Bass recently launched a task force targeting organized retail theft.

A federal law that took effect in June, called the INFORM Consumers Act, addresses the problem in another way, by requiring online marketplaces like Facebook Marketplace and eBay to verify the identities of high-volume sellers.