ORINDA, Calif. >> Four people were killed and at least three wounded at a Halloween night party shooting at a rental house in a wealthy San Francisco Bay Area community and two were killed at party to celebrate the holiday in eastern Utah, authorities said today.

The home in the San Francisco suburb of Orinda had been rented out on Airbnb for what the renter said would be a family reunion, the home’s owner said. But more than 100 people showed up and police were called to the house late Thursday night, police Chief David Cook told the East Bay Times.

Authorities initially reported that four people were wounded but the Contra Costa County Sheriff’s Office said later that the exact number of wounded victims was unknown because some of those injured went on their own to hospitals.

In Utah, a 22-year-old man was stabbed to death and a 23-year-old man was fatally shot at a party where about 20 people were drinking, said Duchesne County Sheriff Travis Tucker. It happened near the small town of Roosevelt east of Salt Lake City in a rural area that relies heavily on oil drilling.

No suspects had been arrested in either case by late this morning.

In the Orinda shooting, one of the people wounded 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. He said he could not specify the types of injuries.

Michael Wang, who owns the 4,000-square-foot house, 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.

Airbnb is “urgently investigating” what happened, spokesman Ben Breit said in an email.

Police did not immediately provide information about the victims or what prompted the violence home a half-mile from downtown Orinda. The four-bedroom home with high vaulted ceilings and woodsy views last sold for $1.2 million in 2017.

Video from the scene posted by KGO-TV showed patients being loaded into ambulances as others limped away from the scene.

Residents of the neighborhood were frustrated with the party’s noise before the shooting, said neighbor Chris Gade.

“It was just more of a noise complaint that we were worried about originally,” he told reporters.

Then Gade said he heard gunshots and saw people “screaming and fleeing down the hill.”

“I think everybody in our neighborhood immediately locked our doors and started messaging each other, trying to figure out what was going on,” he said. “This just doesn’t happen in Orinda.”

Orinda Mayor Inga Miller told KCBS Radio she had not previously heard of any complaints about short-term rentals in the neighborhood. Orinda, population about 20,000, requires short-term rental hosts to register with the city annually and pay an occupancy tax. The maximum occupancy is two people per bedroom plus three people not assigned to bedrooms.

“It’s a very somber day here in Orinda,” she said.