A shocking story is emerging from Half Moon Bay, California, where four workers were killed in a shooting last week. The suspect, a local man, has now admitted to the killings in an interview with police and a jailhouse interview with NBC News.

The suspect, who has not been identified, claims he was bullied by his coworkers and says the shooting was a result of his mental illness. He also reportedly told police that a bill for $100 in equipment triggered the shooting.

The suspect is believed to have worked on the farm where the killings took place, which had experienced a separate shooting last summer.

The District Attorney has confirmed the suspect’s claim that the shooting was triggered by the $100 bill, and his attorney has said that he is pleading not guilty by reason of insanity.

This story is still developing, with more details expected to emerge in the coming days.