Burglars have capitalized on chaos nationwide in the wake of the death of George Floyd, a black man who pleaded for air as a white Minneapolis officer held a knee on his neck. They are allegedly communicating with each other via messaging apps during heists and using the protests and other tactics to throw police off their trail. While opportunists have sometimes joined the frenzy, police and experts say there is a sophistication that suggests a level of planning that goes beyond spontaneous acts.

It’s hardly the first time legitimate protest has been used as a cover for crime. But crime experts, as The Associated Press reported, note the scale of the thefts, which have taken place coast-to-coast, in big and small cities and in suburbs.

“It was very strategic,” Sgt. Ray Kelly of the Alameda County Sheriff’s Office said about the auto thefts and other recent heists in the San Francisco Bay Area community.

Kelly said the county began to get a handle on things after imposing evening curfews on Monday. He noted there was a clear distinction between protesters who got out of hand while demonstrating for social justice and other people who seized on the uprising to steal.

“Some of the burning was done out of anger and that was understandable,” he said. “But the strategic looting was definitely for personal gain. It was not to push forward the community concerns around police brutality and reform.”

Some shoplifters displayed surprising brazenness, walking out of stores with stolen goods. TV helicopters captured some people changing into their pilfered attire outside Long Beach shops and another person struggling to close the trunk of a car stuffed with clothes at a Walnut Creek mall near Oakland.

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“I’ve been a student of these things. And I have never seen anything like it,” said Neil Sullivan, a nationally recognized expert on mass-events security and retired Chicago Police Department commander.

People who stole during civil-rights protests in the 1960s, he said, tended to be individuals who saw crimes of opportunity as demonstrations spun out of control. By contrast, many of the break-ins that have happened the last week appear to be meticulously planned and coordinated, he said.

One of the first of these crimes unfolded Saturday in Emeryville, a tiny city of retail shopping centers next to Oakland, when a crowd showed up and broke into stores after an Instagram post said they would “hit” the Target and “break every stores” (sic).

“This wasn’t the mafia and organized crime, but this wasn’t individuals acting alone,” said Emeryville Mayor Christian Patz. “There definitely was some organization.”

Police in a small San Francisco Bay Area community were about to help authorities in neighboring Oakland keep the peace during a protest when a more pressing crisis hit home: groups of thieves were pillaging malls, setting fire to a Walmart and storming a car dealership.

By the time San Leandro officers arrived at the Dodge dealership, dozens of cars were gone and thieves were peeling out of the lot in $100,000 Challenger Hellcat muscle cars. Nearly 75 vehicles were stolen Sunday, including models driven through glass showroom doors to escape.

The brazen heist, carried out by well-coordinated criminals, was one of many thefts nationwide in the last week at big box electronics stores, jewelry shops and luxury designers. Many of the smash-and-grab thefts have happened during or following protests over the death of Floyd.

In New York, some people stealing from stores were using encrypted messaging to communicate and posted lookouts to warn if police were coming.

In the Southern California city of Long Beach, groups of thieves hit store after store Sunday as marchers demonstrated nearby.

Police in Los Angeles, which had widespread burglaries for several days, said the crimes didn’t occur until a third night of protests and shifted from thieves on foot to those in cars able to haul more off.

The arrival of more than 1,000 National Guard troops in Los Angeles County to provide security freed up officers to more aggressively try to stop crimes. Sheriff Alex Villanueva said his department was able to thwart “a very significant operation to sack” a large outlet mall in the nearby City of Commerce. Dozens were arrested.

“They were there for only one purpose and that was to loot,” he said.

In the San Francisco Bay Area, tweets warning of looting and rioting turned out to be false, though they led some businesses to close and may have been attempts to divert police elsewhere. Richmond police tweeted that a bogus rumor on social media of an officer being shot occurred around the time a pot shop was ransacked.

Groups of thieves struck a series of big box stores on Chicago’s South Side on Sunday while periodically calling 911 to falsely report that a mall several miles away was being ransacked, Alderman Ray Lopez said.

By the time police rushed to the mall to find no one there, the thieves had moved on to another large store — and phoned in additional false reports to again shake police off their trail.

“It was a game of whack-a-mole,” Lopez said.

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In other instances, 10 or more cars would pull up to a store, smash the windows, then wait nearby to see if police would arrive. If they didn’t, some of the same cars would return to load up with goods and speed off.

A reluctance of officers to use force amid intensified scrutiny of police tactics has emboldened would-be thieves, said Eugene O’Donnell, a professor of police studies at New York’s John Jay College of Criminal Justice.

“All you have to tell police is to do nothing and they will do nothing,” he said. “And they are implicitly being told, ‘Don’t do anything.’”

The Associated Press contributed to this report.