The first bit of evidence has emerged about a volatile, violent past involving former coworkers and Half Moon Bay mass-shooting suspect Zhao Chunli, and this comes via a restraining order that was filed ten years ago.

The Chronicle has quickly unearthed court records from Santa Clara County in 2013 that detail how Zhao Chunli, now 66, had a restraining order filed against him in San Jose by a roommate who was also a coworker at a local restaurant. That roommate, Jingjiu Wang, claimed in court documents that Zhao threatened his life, demanded money from him, and tried to smother him with a pillow.

"Mr. Zhao said to me, today I am going to kill you,” Wang writes in the court document that the Chronicle discovered. "He then took a pillow and started to cover my face and suffocate me. While I couldn’t breathe, I used all my might within the few seconds to push him away with my blanket."

We don't know details about the conflict between the two men, only that Zhao apparently quit his job at the restaurant where they both worked on March 10, 2013. (The Chronicle could not locate Wang for comment.) Zhao then allegedly demanded paychecks from Wang two days later, and demanded help getting his job back. The conflict escalated to the pillow attack, and the subsequent restraining order. Another roommate reportedly witnessed the altercation.

On March 14, 2013, Wang claimed that Zhao confronted him in the apartment kitchen, again about getting his job back, and, according to Wang, Zhao said he "would use a kitchen knife to split my head."

The conflict, stemming from some kind of workplace grievance, is looking similar to whatever unfolded in Half Moon Bay. Authorities have only confirmed that the shooting that took place Monday, in which eight people were shot, seven of them fatally, likely stemmed from workplace conflict. Zhao was reportedly a coworker at two mushroom farms to the eight victims.

The Chronicle also got a second-hand story from the son of a man who owned a Cupertino restaurant where Zhao once worked for six months. This incident appears to have been a few years before the San Jose incident with Wang, but it also involved a conflict with a coworker over money — and Zhao was allegedly fired for trying to "suffocate" a coworker.

It appears the 2013 temporary restraining order was not a hindrance to Zhao legally obtaining and registering two weapons. The San Mateo County Sheriff's Office has said that Zhao legally possessed the weapons he had on him Monday, and that they had no reason to consider him a "red flag" up to that point.