The killer was going to have a disciplinary hearing the day of the killings for 'inappropiate racial remarks'.
https://nypost.com/2021/05/28/san-jose-gunman-faced-disciplinary-hearing-on-day-of-attack-report/
I wouldn't automatically believe anything said by co-workers or management. After such incidents, the people who drove the shooter to it NEVER admit what they did to contribute to it.
At 2 places I worked (one retail sporting goods & one Govt. Aerospace Plant), the harassment & bullying included my supervisor sabotaging my work, then writing me up for it & telling lies about me to VP's & management, trying to get me fired.
In a retail sporting goods outlet, co-workers were stealing money and also illegally selling products (including guns & ammunition) to their friends for next to nothing, and no legal paperwork or registration which is required by law for firearms, either.
They were very concerned that I wasn't stealing anything since they knew that I knew what they were doing & that made them afraid I would tell the owner. They frequently offered cash & free guns & ammo to me so I would be a part of it & they could stop worrying about me.
Then the harassment started - including threats on my life.
They will never know how lucky they were that I detested violence more than I detested them.
Officers from the BATF (Bureau of Alcohol, Tobacco & Firearms) descended on the place & arrested 3 of my co-workers AND 2 Managers.
I took legal action against both places. Successfully.