SUNNYVALE (CBS SF) — Police arrested an 18-year-old Wednesday for a shooting at a large house party in Sunnyvale that killed one person and injured another in August.

The Sunnyvale Department of Public Safety said Thursday the arrest of Sean Andrew James Jr. followed months of detective work to identify the shooter.

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On August 7, officers responded to a report of a party of some 150-200 people at a house on the 1400 block of Navarro Drive. As officers arrived, they heard several gunshots coming from the home and once inside found two men suffering from gunshot wounds, Sunnyvale DPS said.

Sean Andrew James Jr. (Sunnyvale DPS)

Officers provided medical care until medics arrived. Both victims were taken to a local hospital where one later died of his injuries.

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On Wednesday, Sunnyvale DPS found James Jr. at a residence on the 1000 block of Aster Avenue in Sunnyvale. A search warrant was served at the residence and several handguns and ammunition were recovered.

While James Jr. is now 18 years old, at the time of the shooting he was 17; he was booked into the Santa Clara County Juvenile Hall on one count of murder and one count of attempted murder.

The investigation was ongoing and Sunnyvale DPS urged anyone with information about the case to contact Detective Corinne Abernathy at (408) 730-7134 or cabernathy@sunnyvale.ca.gov.

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