A gunman killed seven people in two locations in Half Moon Bay, California, on Monday, shaking a state still mourning another mass shooting just days before.

The police arrested Zhao Chunli, age 67, of Half Moon Bay in connection with the shootings after he was found in his car in the parking lot of a San Mateo County Sheriff’s Office sub-station in the town, the sheriff’s office said, and there was no continuing threat to the community.

He was taken into custody “without incident” and was “fully cooperating”, Sheriff Christina Corpus said. Investigators believe he acted alone, she said.

Investigators have not established a motive, according to Captain Eamonn Allen of the sheriff’s department. The local authorities were working with the FBI and had not uncovered a criminal history or past incidents at either of the scenes, he said.

Governor Gavin Newsom of California wrote on Twitter that as news of the shooting broke, he had been at a hospital, meeting victims of a mass shooting on Saturday in Monterey Park. In that attack, a gunman fatally shot 11 people.

“Tragedy upon tragedy,” he said.

Monday’s shootings took place around 2:20pm (local time) in Half Moon Bay, a rural seaside town between San Francisco and Santa Cruz. The beaches are a popular surfing destination, and the inland mountains are home to one of the state’s oldest agricultural communities, which employs migrant workers.

At least one of the two locations was a plant nursery, the sheriff’s office said. “There were farm workers affected tonight. There were children on the scene at the incidents. This is a truly heartbreaking tragedy in our community,” San Mateo County Supervisor Ray Mueller said in a news conference, where he alluded to the storms that have pounded the area in recent weeks.

“The amount of stress that’s been on this community for weeks is really quite high.”

Four people were found dead at a location near Highway 92, and a fifth person with life-threatening injuries was taken from that site to Stanford Medical Center, according to the sheriff’s office.

Three more people were found dead about a mile away, on the outskirts of the city.

The sheriff’s office said late on Monday that it was working to identify the victims and notify their families. All the victims were adults, but some workers lived at the location of one of the shootings along with children, Sheriff Corpus said.

“It was in the afternoon, when kids were out of school,” she said. “For children to witness this is unspeakable.”

New York Times News Service