Police tape is placed near the scene of a shooting Monday, Jan. 23, 2023, in Half Moon Bay, Calif. Seven people were killed in two related shootings Monday at a mushroom farm and a trucking firm in a coastal community south of San Francisco, and officials say a suspect is in custody. (AP Photo/Jeff Chiu)

HALF MOON BAY, Calif. (AP) — A gunman killed seven people at two agricultural businesses in Northern California, plunging the state into mourning again in the wake of its third mass killing in eight days.

Officers arrested a suspect in Monday’s shootings, 67-year-old Chunli Zhao, after they found him in his car in the parking lot of a sheriff’s substation, San Mateo County Sheriff Christina Corpus said.

Seven people were found dead and an eighth injured at a farm and another location several miles away, the Sheriff’s Office said. Officials believe Zhao worked at one of the facilities and that the victims were workers as well, Corpus said. Officials haven’t determined a motive for the shooting.

California is still reeling from an attack on a Lunar New Year celebration in Monterey Park that killed 11 and cast a shadow over an important holiday for many Asian-American communities. Authorities are still seeking a motive for the Saturday shooting.

“For the second time in recent days, California communities are mourning the loss of loved ones in a senseless act of gun violence,” President Joe Biden said Tuesday morning. “Even as we await further details on these shootings, we know the scourge of gun violence across America requires stronger action.”

The new year has brought six mass killings in the U.S. in fewer than three weeks, accounting for 39 deaths. Three have occurred in California since Jan. 16, according to a database compiled by The Associated Press, USA Today and Northeastern University. The database tracks every mass killing — defined as four dead not including the offender — committed in the U.S. since 2006.

The killings occurred on the outskirts of Half Moon Bay, a city about 30 miles (48 kilometers) south of San Francisco.

Half Moon Bay Vice Mayor Joaquin Jimenez said the victims included Chinese and Latino farmworkers. Some workers lived at one of the facilities and children may have witnessed the shooting, she said. Corpus said it wasn’t immediately clear how the two locations were connected.

The Sheriff’s Office first received reports of a shooting in the afternoon and found four people dead and a fifth wounded at the first scene. Officers then found three more people fatally shot nearby, Capt. Eamonn Allen said in a news release.

About two hours later, a sheriff’s deputy spotted Zhao’s car parked outside a sheriff’s substation in a strip mall and arrested him.