SAN FRANCISCO (CBS SF) — The San Francisco division of the ATF announced Thursday that guns seized during new raids connected to the Orinda Halloween mass shooting have been linked to other Bay Area shootings.

Five people died and nine were injured at a house party at an Airbnb rental at 114 Lucille Way on Halloween night.

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Multiple people were arrested in connection with the shooting last Thursday, but most of the suspects were released when Contra Costa County prosecutors decided not to file charges on Monday.

The San Francisco division of the Bureau of Alcohol, Tobacco, Firearms and Explosives posted photos and made the announcement via its Twitter account Thursday evening.

Pictures show ATF personnel in heavily armed vehicles during a raid made as the agency assisted Contra Costa County authorities in the investigation into the Orinda shooting. 

The agency did not specify if the photos were from the raids that took place last Thursday during the initial arrests or if a more recent raid with new arrests had taken place.

However, late Friday morning, the Contra Costa Sheriff’s office confirmed that additional arrests had been made in connection with the Orinda shooting, but provided no additional details.

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The ATF said the national ballistics database linked some of those guns to other shootings in the Bay Area, but the agency did not offer any details on what shootings the weapons were connected to.

The ATF also announced a reward of up to $20,000 being offered for information on the mass shooting on Halloween in Orinda that killed five.

The ATF said the reward is contingent on information that leads to the arrest and conviction of the person or persons responsible for the shooting.

Anyone with information about the shooting is asked to call the ATF at (888) 283-8477 or visit or via the “reportit” app available on Google Play and the Apple App Store.

All calls will be confidential.

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