Chunli Zhao, 67, was charged with seven counts of murder, one of which was attempted murder for the Half Moon Bay shooting that took place on January 23.

However, Zhao, the alleged perpetrator of what prosecutors called the "deadliest attack in the county's history", denied all charges against him during his hearing on Thursday.

Zhao was found in his parked vehicle after the shooting, where police also found a semi-automatic handgun. Sheriff Christina Corpus told reporters: "Shortly thereafter three additional victims were also located deceased with gunshot wounds at a separate shooting scene." It was reported that the suspect was known to have been a "disgruntled worker."

Elizabeth Hill, San Mateo County Superior Court Judge scheduled the next court hearing for May 3 since Zhao's attorneys asked for time to review the evidence.

The suspect was taken into custody two hours after seven Chinese agricultural workers were killed and one injured in the mass shooting. 

According to the nonprofit group Gun Violence Archive, as of February 16, there have been 72 mass shootings and 2,337 deaths, including 29 children and 196 teenagers, as a result of gun violence in the United States.

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