GILROY (CBS SF) — Authorities in South Bay on Tuesday morning arrested one subject and seized a gun after serving multiple warrants in connection with their investigation into a fatal Halloween party shooting at the home of a Gilroy city councilmember.

The shooting was reported shortly before 1 a.m. on Oct. 30th at the home of Gilroy City Council Member Rebeca Armendariz on the 400 block of Las Animas Avenue, where a large outdoor party was taking place. One person was killed and three were injured.

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Police said there was an altercation before the shooting and that at least one person fired a gun. The four victims’ ages range from 17 to 19 years old.

Friends later identified the teen who died as 18-year-old Michael Zuniga-Macias.

According to the release issued by Gilroy Police, on Tuesday morning officers with the department were assisted by the Santa Clara County Sheriff’s Office, the Santa Clara Police Department, the Santa Clara County Specialized Enforcement Team, and the Santa Clara County District Attorney’s Office as they served search warrants at three different locations in Gilroy related to the fatal Oct. 30th shooting in the 400 block of Las Animas Avenue.

Police said they searched locations on the 9200 block of Calle Del Rey, the 8800 block of Fuchsia Court, and the 7600 block of Rosanna Street.

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During the search of one of the locations, a firearm was located. 18-year-old Lucas James Tomasetti was subsequently arrested at the scene without incident. He was charged with being a felon/prohibited person in possession of a firearm and later booked into the Santa Clara County Jail. Police did not say if Tomasetti was a suspect in the Oct. 30th shooting.

Police said it was unknown if the firearm seized was used during the shooting.

Authorities previously said they are searching for at least two gunmen in connection with the fatal Halloween party shooting.

Police arrested 19-year-old Benjamin David Calderon less than 24 hours after the deadly shooting, but he was later released after the Santa Clara County District Attorney’s office declined to charge him.

“We have declined to file charges pending further investigation. This was a large, chaotic Halloween party that ended with a tragic shooting and homicide,” said Santa Clara County Chief Trial Deputy District Attorney in a statement released last week.

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Members of the Gilroy Police Department’s Investigations unit — along with the Anti-Crime Team (ACT) — are actively investigating the fatal shooting. Anyone with information is asked to please contact Detective Silva at (408) 846-0335. Parties wishing to remain anonymous may call the Tip Line at (408) 846-0330.