Investigation into VTA gunman Samuel Cassidy ongoing

Law enforcement officials announced Thursday that Samuel Cassidy, the VTA employee who opened fire and killed nine of his colleagues Wednesday morning, used a timer to set his house on fire at the exact same time he began the shooting. KTVU's Tom Vacar reports on Thursday's developments and the continued investigation at Cassidy's residence.

Most mass shooters share one very commonplace trait: Anger

While some people might portray mass shooters as monsters or having a mental illness that makes violence impossible to prevent, a recent study suggests that most mass shooters share one very commonplace trait: Anger

What we know about the VTA light rail gunman Sam Cassidy

The alleged gunman in a San Jose shooting that left 9 dead, including the shooter, was identified as a VTA employee. An ex-girlfriend called him abusive, co-workers called him “strange,” and at least one neighbor said he had a hot temper.