Orinda, California — Four people were killed and at least four people were injured in a shooting at a Halloween party at a rental home in a wealthy San Francisco Bay Area community, officials said. The shooting Thursday night in Orinda, near Oakland, happened at a party attended by 100 people, police chief David Cook told reporters during a press conference Friday.

Cook said no arrests have been made in the case, but he said there was no reason to believe there was an ongoing threat to the community. The chief said there was no reason to believe whoever was behind the shooting stayed in the area because the house was rented by people who aren't from Orinda.

Michael Wang, who owns the home, said he rented it out to a woman through Airbnb for what the woman said would be a family reunion for a dozen people, according to The San Francisco Chronicle. Wang said his wife reached out to the woman after neighbors called complaining about excessive noise. The woman said there were only 12 people at the party, but Wang said he could see more people via video from his Ring doorbell camera.

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According to social-media posts, an "AirBNB mansion party" had been advertised for Thursday night, CBS San Francisco reported.

Airbnb spokesman Ben Breit said in an email that the home's Airbnb ad included prohibitions on parties, weapons, smoking and marijuana use. The listing also said quiet hours must be observed between 10 p.m. and 8 a.m. because neighboring homes are close by.

Breit said Airbnb has banned the renter from its platform and the home has been removed as a listing.

Police did not immediately provide information about what prompted the violence at the home, which is located in a neighborhood of multimillion-dollar houses and last sold for $1.2 million in 2017.

The shooting was first reported around 10:30 p.m. Video from the scene showed multiple patients being loaded into ambulances as others limped away from the scene. Video also showed police talking to people who appeared injured.

At least four people are dead and several others wounded after gunfire erupted at a Halloween party in Orinda, Calif., Thursday night, officials say; there is no confirmed information about the number of victims or their conditions https://t.co/plxovGJgYH pic.twitter.com/HHGexpg4Uw — CBS Evening News (@CBSEveningNews) November 1, 2019

One patient was in critical condition at the John Muir Medical Center in the nearby city of Walnut Creek, hospital spokesman Ben Drew said. Another patient was in serious condition and a third was treated and released.

The California Highway Patrol and other agencies were called to the scene due to the size of the crowd at the site, Cook said. Police told CBS San Francisco they were overwhelmed by the crowd where the shooting happened.

"It's a very somber day here in Orinda," Mayor Inga Miller told KCBS Radio.

City officials had regulated the short-term rental industry with an ordinance and a registry. City Manager Steve Solomon told reporters the property was registered with the city.

The city opened two code-enforcement cases into the property — regarding trash containers in July and noise in March — and they were closed when the property came back into compliance with the ordinance, Solomon said.