The gunman, a maintenance worker at a transit agency in Silicon Valley, killed nine of his colleagues years after federal officials uncovered a notebook with his complaints.
There are troubling allegations that date back more than a decade for the man accused of killing nine people and injuring multiple others at a San Jose railyard on Wednesday morning.
Police secure the scene of a mass shooting at a rail yard run by the Santa Clara Valley Transportation Authority in San Jose, California, May 26, 2021. REUTERS/Peter DaSilva