Updated October 2, 2023 at 3:51 PM ET

Authorities in Philadelphia have charged 72 people for allegedly ransacking businesses in multiple neighborhoods across the city last week.

Images and videos shared by police and posted on social media showed perpetrators bursting into stores in large numbers on Tuesday and Wednesday and quickly fleeing with stolen merchandise.

Prosecutors said Monday that 67 adults and five juveniles face charges from criminal mischief to conspiracy and felony burglary.

According to Philadelphia District Attorney Larry Krasner, only a few of those arrested are underage but a "very large number" are between the ages of 18 and 25.

"In general, what we are seeing is that most of them have no criminal record or a minimal criminal record," Krasner said. "But that isn't all of them. There certainly are some people in this group who are much more concerning than others."

Authorities said they expect to charge more people in the coming days.

The unrest began Tuesday evening shortly after a peaceful protest over a judge's decision to drop all charges against a Philadelphia police officer who shot and killed a driver last month.

Interim Police Commissioner John M. Stanford Jr. stressed that the incidents were not connected with the protest: "What we had tonight was a bunch of criminal opportunists take advantage of a situation and make an attempt to destroy our city," he said in a press conference Tuesday night.

On Wednesday, the police department said it would have an increased presence throughout the city and warned that officers were "ready to make more" arrests.

Video on social media showed thieves breaking into an Apple Store, and groups also stole from a Foot Locker, a Lululemon and a liquor store, the Philadelphia Inquirer reported.

The Pennsylvania Liquor Control Board closed all of its retail locations in the area Wednesday "in the interest of employee safety" and pending an assessment of the damage and losses, liquor board spokesperson Shawn M. Kelly told NPR.

"At least 18 Fine Wine & Good Spirits stores in Philadelphia were looted" on Tuesday night, Kelly said. "Fortunately, no employees were hurt, although some were understandably shaken."

Philadelphia is the latest city to see dramatic scenes of large-group smash-and-grabs, which have been documented across the country in recent years, though it's unclear whether such crimes are actually increasing.

Still, retailers have been raising the alarm on thefts in their businesses. Target said Tuesday that it is closing nine stores in four states, citing theft and organized retail crime, which involves large-scale criminal operations that steal and resell merchandise.

A National Retail Federation survey estimated that "shrink" — the industry term for losses — amounted to $112.1 billion in 2022, up from $93.9 billion in 2021. Those figures are based on self-reported data by businesses and other groups, and also include losses from employee theft, cashier errors, incorrect pricing and more.

In Philadelphia, Stanford said the thefts began around 8 p.m. in Center City, with a crowd growing to as large as a hundred people.

Authorities then began to get 911 calls about looting in different neighborhoods, which he believes people had been discussing online. "We were able to link some things on social media and see that there was some chatter about certain locations," Stanford said.

Several vehicles and a police cruiser were vandalized, and police recovered at least two firearms during the arrests, though it was unclear if the weapons were linked to the unrest Tuesday evening.

Drew Neckar, president of Security Advisors Consulting Group, said it's difficult to disrupt large-group smash-and-grabs because of how quickly they occur and how many people are involved.

"No store can have the level of security to be able to withstand or have security employees in place to stop a hundred people coming through the door intent on looting," he said.

Neckar added that once thieves are inside, most retailers tell their workers and security guards to "back off and be a good witness, which is the correct thing to do, because you don't want people to get hurt when you might just lose inventory and dollars."

Some retailers have taken other steps to reduce their likelihood of being targeted by large groups of thieves in the first place, such as installing laminated glass and keeping high-value merchandise in a secure area of the store, he added.

Copyright 2023 NPR. To see more, visit https://www.npr.org.