Witnesses described hearing gunfire and seeing chaos erupt as some 100 terrified partygoers fled the home Thursday night in Orinda, a quiet and wealthy suburb about 15 miles (24 kilometers) from San Francisco that has seen only two previous killings this century, the San Francisco Chronicle reported.

No arrests had been made and there was no immediate word on a motive for the attack. Two guns were found at the property, authorities said.

Three people, all from the Bay Area, died at the scene and a fourth died at the hospital, authorities initially said. The Contra Costa County Sheriff's Office identified them Friday evening as 22-year-old Tiyon Farley of Antioch, 24-year-old Omar Taylor of Pittsburg, 23-year-old Ramon Hill Jr. and 29-year-old Javin County. The sheriff's office identified a fifth victim, 19-year-old Oshiana Tompkins of Vallejo and Hercules, late Friday night, saying she died at a local hospital.

Other people were wounded by gunshots or injured in the panic that followed, authorities said.

The party apparently was advertised on social media. One attendee said he was enjoying the music and watching people dance when he heard shots and people started running.

The screaming seemed to last forever, said Devan, who asked that his last name not be used because he feared for his safety.

"Everybody started running, scrambling," he said. "People were just collapsing and friends were helping friends. It was a scary situation and then as everyone is panicking and stuff, there were more shots."

Devan shot a video posted to Instagram that showed a wounded man on the ground and a police officer standing over him and a woman saying she needs to go to the hospital "because my hand's been blown off."

On Friday, police tape surrounded the block as people came to collect their cars and other belongings. One woman in tears told reporters the father of her child had been killed. She left before giving her name.

Romond Reynolds picked up the car of his son, 24-year-old Armani Reynolds, who he said was left comatose by the shooting.

"All I know is that he's a victim and was at the wrong place at the wrong time," Reynolds said.

The four-bedroom home had been rented on Airbnb by a woman who told the owner her dozen family members had asthma and needed to escape smoke from a wildfire, the person with knowledge of the transaction told The Associated Press. A fire burning in Sonoma County about 60 miles (97 kilometers) north of Orinda earlier in the week fouled the air over a wide area.

The owner was suspicious of a one-night rental on Halloween and before agreeing reminded the renter that no parties were allowed, said the person with knowledge of the transaction, who was not authorized to publicly disclose the information and spoke only on condition of anonymity.

The owner, Michael Wang, said his wife reached out to the renter Thursday night after neighbors contacted them about the party. The renter said there were only a dozen people at the home but Wang said he could see more people on video from his doorbell camera.

"We called the police. They were on the way to go there to stop them, but before we got there the neighbor already sent us a message saying there was a shooting," he told the Chronicle.

Neighbor Shahram Saki, 61, said in a phone interview that some fleeing partygoers hid in the bushes in his front yard and others begged to be let into his home.

"They were screaming for help. I told them, 'You gotta get out of here,'" Saki said. "I was scared to death, anything could have happened."

Orinda city documents show officials issued violations in March for exceeding the home's maximum occupancy and illegal parking. City Manager Steve Salomon said the homeowner had resolved previous complaints lodged in February over occupancy and noise and in July over overflowing trash.

Orinda, with a population of about 20,000, requires short-term rental hosts to register with the city annually and pay an occupancy tax. The maximum occupancy is 13 people.

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

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