Montebello police arrested a man on Tuesday who was suspected of fatally shooting a Long Beach resident with an assault rifle during an attempted jewelry sale the day before, authorities announced in a press release.

Officers arrested Montebello resident Sean Matthew Garcia, 25, for the murder of 28-year-old Long Beach resident Brian Lee Gomez on Tuesday, September 29 at about 6:45PM, the release stated on Wednesday.

The day before the arrest, investigators believe Gomez met up with Garcia on the 1600 block of Neil Armstrong Street in Montebello just before 6:30PM to sell Garcia a $2,000 gold chain.

During that time Garcia then appeared with an assault rifle, chased down Gomez and shot him on the sidewalk and street area at commuter time, police said.

Investigators used the website offerup.com—where police believe Gomez and Garcia first connected to arrange the sale—and other resources to identify Garcia as the suspect.

Montebello police then executed a search warrant at Garcia’s residence and found evidence linking Garcia to the crime—including assault rifle parts believed to be from the weapon authorities allege Garcia used.

Police also found methamphetamine at the residence, authorities said.

“During the investigation, we were able to find out that there were other victims of this particular person that were robbed basically in the same area,” Montebello police Chief Kevin McClure said at a Wednesday news conference.

Investigators learned of a robbery victim whose assault rifle—similar to the weapon used in Gomez’ homicide—was allegedly taken by Garcia based on evidence linking him to the crime, authorities said.

Officials said that crime was never reported.

The Montebello Police Department is looking for additional victims who are encouraged to contact the department’s Investigation’s Bureau at 323.887.1313 ext . 262.

City News Service contributed to this report.

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