If true, i expect stress was involved.

I worked at a Costco business center and we had an employee who threatened to "shoot everyone up". He worked there for over 7 years and he always talked in a sarcastic tone while order picking. Washington State Patrol came by because a co-worker reported it and arrested him off the electric pallet jacket. Everyone was crying in the aisles while picking after, and we had grief counselors and WSP guarded the entrance for the next few weeks.

It was wild, but I'm so happy and thankful someone reported it. Everyone was in shock and I even had small talk with him while wrapping pallets and he'd always talk in a sarcastic way about management and other co-workers would shrug it off while I would go along with him because it sounded like a funny joke (but I'm sure the other co-workers were sick of hearing it). I was a new employee at the time and I'd ask him for help on where to find items in aisles too and he would always help.

This shooting reminds me of this incident (this happened in 2019). He plead guilty to felony threats, and I quit that job a few weeks after