Suspect in Half Moon Bay Shooting Pleads Not Guilty

At the farm, there had been a disagreement over whether Mr. Zhao had been operating a forklift that collided with another vehicle on the farm, Mr. Wagstaffe said. A supervisor told Mr. Zhao that he had to pay for the damage. Mr. Zhao, enraged, later shot the man, Mr. Wagstaffe said.

“Obviously it’s not what caused this, because there was a long buildup to it over the course of some time,” Mr. Wagstaffe said in a phone interview. “But this dispute might’ve been what, in his mind, was the final straw.”

Every person shot was specifically targeted, Sheriff Christina Corpus of San Mateo County said last month.

During a manhunt following the shootings, sheriff’s deputies found Mr. Zhao’s cellphone lying on the side of the highway, an apparent attempt to prevent law enforcement from tracking him, Sheriff Corpus said. Deputies apprehended Mr. Zhao hours later in a parking lot near a sheriff’s station, she said, where they found him lying back in the driver’s seat with a semiautomatic pistol on the passenger seat.

Mr. Wagstaffe said last month that Mr. Zhao’s media interview wouldn’t affect how prosecutors build their case against the suspect. He had already admitted to detectives that he had committed the mass shootings, Mr. Wagstaffe said.

“The issue in the case is going to be what exactly was his mental state,” Mr. Wagstaffe said.

On Wednesday, Mr. Wagstaffe said that he could not provide further information about the case because Judge Lee issued a gag order last week. The ruling prohibits the D.A.’s office, Mr. Zhao, his defense lawyers and the San Mateo sheriff’s office from speaking publicly about the facts of the case or offering opinions on it.

Mr. Zhao’s lawyers had requested the order, Mr. Wagstaffe said, “naming me specifically as talking too much about the case.”

Mr. Zhao, who waived his right to a have a preliminary hearing within 10 court days, is scheduled to return to San Mateo Superior Court in May.