Seven people have been killed at two locations in related mass shootings in a small Californian coastal city.
Four people were killed at a farm and another three at a trucking business, several miles away, on the outskirts of Half Moon Bay, a city around 30 miles (48km) south of San Francisco.
The incidents mark the state's third mass killing in eight days, following Saturday's attack at Monterey Park that killed 11 at a Chinese New Year celebration.
Police arrested 67-year-old Chunli Zhao in connection with the latest shootings, after they found him in his vehicle in the car park of a police station, San Mateo County Sheriff Christina Corpus said.
Half Moon Bay vice mayor Joaquin Jimenez said the victims included Chinese and Latino farmworkers.
It was not immediately clear how the locations were connected, though it is believed the suspect worked for one of the businesses.
"We are sickened by today's tragedy in Half Moon Bay," said Dave Pine, president of San Mateo County board of supervisors.
"We have not even had time to grieve for those lost in the terrible shooting in Monterey Park. Gun violence must stop."
Television footage showed officers taking the man into custody, with the San Mateo County Sheriff's Office tweeting the news after receiving reports of the shooting at 2.30pm local time (10.30pm GMT).
On his arrest, Zhao got out of the car, where officers pulled him to the ground, put him in handcuffs, and led him away. A weapon was found in his vehicle, officials said.
Officials have not yet determined a motive for the shooting but believe Zhao acted alone.
Aerial images also showed police officers collecting evidence from a farm with dozens of greenhouses.
The area, Half Moon Bay, is home to around 12,000 people and is known for producing flowers and vegetables. It was described by Senator Josh Becker, who represents the area, as a "a very close-knit" agricultural community.
Six mass shootings in less than three weeks
In less than three weeks, the US has seen six mass shootings, accounting for 39 deaths.
Three have occurred in California since 16 January, according to a database compiled by The Associated Press, USA Today and Northeastern University.
A teenage mother and her 10-month-old baby were fatally shot in the head "assassination style" in an attack that left six people dead in central California on 16 January.
Police said a gunman fired multiple rounds into the skull of 17-year-old Alissa Parraz and killed her child, Nycholas, as they tried to run away from the attack.