The California mushroom farm where four people were killed in a mass shooting on Monday was the scene of another alleged attempted murder last year, records show. Chunli Zhao told NBC he opened fire on his co-workers at the California Terra Garden in Half Moon Bay this week because he was bullied and frustrated by having to work long hours. But on July 1 last year, a manager at the same farm named Martin Medina also allegedly threatened to kill a colleague and fired a shot into the man’s trailer. According to a prosecutor, the bullet cut through the trailer and went into a neighboring one which housed Yetao Bing—one of the victims who was killed on Monday. Medina was charged with attempted murder over the incident last summer and had attended a preliminary hearing in court on Monday mere hours before Zhao allegedly opened fire. Authorities say Zhao killed four co-workers and injured a fifth at California Terra Garden before driving to another farm nearby where he was previously employed and allegedly murdering another three victims.