The shooting took place at the VTA's Guadalupe light rail yard, a sprawling maintenance and operations facility near the Guadalupe River in central San Jose. The VTA operates the light rail and bus systems serving Santa Clara County, and the yard was filled with mechanics, technicians, and operators preparing for the day's service. Cassidy, a substation maintenance worker who had been employed by the VTA for more than a decade, targeted specific coworkers as he moved through the facility. The selectivity of the attack suggested long-simmering grievances rather than random violence. Law enforcement arrived to find a scene of devastating loss among people who had been colleagues, some for years.

The nine victims ranged in age from 29 to 63. They were train operators, mechanics, linemen, and maintenance workers, the people who kept Silicon Valley's public transit running. Each was someone's parent, partner, child, or friend. The community that formed around their absence was itself a kind of transit workforce, a network of families connected by shared grief and the knowledge that their loved ones had gone to work on an ordinary Wednesday morning and never come home. The shooting prompted an outpouring of support from across the Bay Area and renewed debates about workplace safety, gun control, and the warning signs that precede acts of mass violence.

In the wake of the shooting, investigators discovered that Cassidy had set a timed incendiary device at his home, which caught fire around the same time as the shooting. The deliberateness of the plan, attacking coworkers while simultaneously destroying evidence at home, pointed to a level of premeditation that deepened the horror. San Jose Mayor Sam Liccardo and California Governor Gavin Newsom spoke at memorial services. The VTA rail yard reopened, but the community of workers who returned did so carrying the weight of what had happened there. A memorial was established to honor the nine employees who died.