A group of nine people armed with hammers entered a jewelry store in Concord and smashed glass display cases to steal jewels, the Concord Police Department confirmed.
According to a press release, the incident happened Tuesday at 7:30 p.m. at the Iceberg Diamonds jewelry store inside the Sun Valley Mall.
Surveillance video shows the group began smashing glass display cases and stole jewels as employees tried to intervene, but they were unable to stop the suspects who got away before police arrived.
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Concord Police Lieutenant Sean Donnelly told NBC Bay Area some people called police reporting what they though were shots fired
"Some people called police reporting what they thought were shots fired, just from the sound, but it was actually the sound of hammers hitting the glass," said Concord Police Lieutenant Sean Donnelly.
He also said the crime took approximately 30 seconds and "it looks like a very well planned crime."
The Bay Area has seen several crime similar to this one, and just a month ago six masked thieves smashed the cases of Valliani Jewelers inside the same mall. Then they attempted to go next door to St. Andews Jewelers, but employees dropped the security gates before they could get in.
St. Andrews Jewelers owner Brian Berglund told NBC Bay Area he's concerned this is a trend involving organized groups.
"I guess you would say its a red alert," he said.
These smash and grab robberies happened close to closing time between 7:30 p.m. and 8 p.m.
"Habitually, that’s when a jewelry store has the least staff and my understanding is the mall has beefed up security and reached out to Concord PD to have additional exposure," Berglund said.
“We’re to the point where if we have customers come in, who we don’t know, we ID them before we show them merchandise."
Concord Police said detectives are investigating possible links between the Sun Valley Mall heists and others in the region.
"It’s always a possibility that they’re connected. We’re doing our best to talk to other law enforcement agencies in the Bay Area to determine if that’s the case.," Lt. Donnelly said.
No arrests have been made in the most recent heist.
Concord Police Detectives continue to investigate the case and urge anyone with information to contact Detective Christine Corey with CPD's Financial Crimes Unit at 925-603-5828.