The Concord Police Department confirmed that a group of nine people armed with hammers entered a jewelry store in Concord and smashed glass display cases to steal jewelry.

According to the press release, the incident took place at 7:30 pm on Tuesday at the Iceberg Diamonds jewelry store in the Sun Valley Shopping Center.

Surveillance video showed that when employees tried to intervene, the organization began smashing glass display cases and stealing jewelry, but they could not stop the suspects who ran away before the police arrived.

Concord Police Lieutenant Sean Donnelly told the NBC Bay Area that some people called the police to report that they were shot dead

Concord Police Lieutenant Sean Donnelly said: "Some people call the police to report what they think is the sound of a gunshot, only to know from the sound, but it is actually a hammer strike. The sound of glass."

He also stated that the crime process lasted about 30 seconds and “looks like a carefully planned crime”.

Several similar crimes have occurred in the Bay Area. Just a month ago, six masked thieves smashed the case of Valliani Jewelers in the same mall. Then they tried to go to St. Andews Jewelers next door, but the employees put down the safety door before they even entered.

Brian Berglund, owner of St. Andrews Jewelers, told NBC Bay Area that he is concerned that this is a trend involving organized groups.

"I guess you would say this is a red alert," he said.

These looting and robberies occurred between 7:30 and 8 pm, close to closing time

"Usually, that is when the jewelry store has the least employees. My understanding is that the mall has strengthened security measures and contacted Concord PD to increase exposure," Berglund said.

"We have reached the point where if we have customers who we don't know come in, we will authenticate them before showing them the goods."

Concord police said that detectives are investigating possible connections between the Sun Valley Mall robbery and others in the area.

"It is always possible for them to be connected. We are doing our best to talk to other law enforcement agencies in the Bay Area to determine whether this is the case." Lieutenant Donnelly said.

No one was arrested in the recent robbery.

Concord police detectives continue to investigate the case and urge anyone with information to contact Detective Christine Corey of the CPD Financial Crime Department at 925-603-5828.