A man walked into his ex-wife's workplace in California and argued with her before he shot her dead. He then turned the gun on himself.

Authorities said the sounds of bullets ringing out in busy mall in Thousand Oaks at 2:15pm sent shoppers running and out the exits Saturday, according to NBC Los Angeles. The incident occurred inside the Paper Source.

The 33-year-old Los Angeles-area gunman was wounded and taken to a hospital, officials said. He was in critical condition. His ex-wife was 30 years old. Their identities have not yet been released.

The man went to a store at The Oaks mall in the city of Thousand Oaks, about 40 miles west of Los Angeles, and had an argument with the 30-year-old victim before shooting her, Ventura County sheriff's Sgt. Eric Buschow said.

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Distraught and frightened shoppers were seen outside hugging after hearing gunshots echo through the mall Saturday after an ex-husband shot dead his wife at her workplace

The mall was placed on lockdown as scores of authorities combed the scene for clues

Law enforcement officers work in The Oaks mall in Thousand Oaks, Calif., about 40 miles (64 kilometers) west of Los Angeles on Saturday

The divorced couple have children, who have been found safe, said Buschow, adding that initial indications show the shooting was a murder and attempted suicide.

The gunshots at the shopping center with open-air and indoor shopping space led to some chaos and a lockdown.

Autumn Montano, 19, was visiting the mall with friends when the the shots were fired.

'All of a sudden we heard people screaming,' she told the Thousand Oaks Acorn. 'We saw everyone running toward the food court so I just freaked out.'

The assistant manager shut the gate to the store's entry and customers and employees sheltered in the stock room.

'My whole body was shaking and my heart was racing,' she said. 'I was really very terrified for sure.'

Jeffrey Simpson, 17, was shopping with his mother at a department store when an announcement came over the intercom about a threat outside the mall.

'I went to Nordstrom to get pants, and the next thing I know, the doors are being sealed,' Simpson said.

He said he and his mom were 'a little shaken' but OK. They were in the store for more than an hour but shoppers were free to move around and employees were helping people stay comfortable and calm, Simpson said.

Matt Lemieux said that he was working on his computer inside a coffee store when he suddenly saw 'a whole group of people' running by.

'It was creepy,' he said.

So far the motive to the targeted shooting is not yet know, authorities say.

As of 4:30pm, the indoor portion of the mall had been reopened.

Deputies were still going store to store looking for potential witnesses, a sheriff's department spokesperson told Thousand Oaks Acorn.

The outdoor portion of the mall will remain closed indefinitely while police investigate.

For confidential support call the National Suicide Prevention Line on 1-800-273-8255.