Half Moon Bay shooting sparked by $100 repair bill, prosecutor says

• Four people were killed at a mushroom farm on the outskirts of Half Moon Bay and three others near a trucking facility less than a mile away. Zhao had been employed at the mushroom farm.
• San Mateo County Sheriff spokesperson Eamonn Allen said at the press conference earlier this week that all evidence pointed to a "workplace violence incident."
• Zhao said in the jailhouse interview that he had been bullied and worked long hours, with the issues going unaddressed, NBC Bay Area reported.

The big picture: Zhao told investigators he was angered by the $100 bill to repair a forklift that was damaged in a collision with a co-worker’s bulldozer, Wagstaffe said, the Bay Area News Group reported.

• Wagstaffe's account confirmed reporting from NBC's local affiliate in the San Francisco Bay Area, which first reported the development.

• Prior to the shooting, Zhao expressed his frustration about the bill to his supervisor and the co-worker, whom he blamed for the collision, but the supervisor insisted he pay, according to Wagstaffe, per AP.
• Zhao then allegedly shot the supervisor and co-worker.
• While Zhao had long felt aggrieved by work-related issues, the repair bill might have "lit the candle," Wagstaffe said, Fox2 KTVU reported.