Four men were shot — one fatally — after two of them volunteered to paint over graffiti on the wall of a neighborhood ice cream shop in Los Angeles, authorities said.

The gunfire erupted Saturday afternoon in the Northridge area of the San Fernando Valley, according to the Los Angeles Police Department.

Shortly before the shooting, two of the men walked into Northridge Ice Cream, the shop's owner, Victor Santoyo, told ABC 7.

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"They said, ‘There is graffiti on the wall. Do you want me to paint the graffiti for you, for free,’" Santoyo said. "I found them a little bit of paint and gave it to them, and then a few minutes later, we hear the gunshots."

A few minutes later, the four men are seen on surveillance video ducking from gunshots, the news station reported.

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A shooter opened fire at a group of people at a neighborhood ice cream shop in Los Angeles, California. (Fox News)

"One guy came in, asking for help. He got shot in the stomach," Santoyo said.

Investigators suspect the shooter was driving a white sedan, police said.

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A man believed to be about 60 years old was killed, police Officer Tony Im said. A man in his 40s was hospitalized in critical condition. The other two victims, who are believed to be about 30 and 40 years old, were also hospitalized, Im said. Police later said one of the victims was treated and released.

Police were seeking witnesses and any other surveillance video from the neighborhood about 20 miles northwest of downtown Los Angeles.