Police and federal investigators on Thursday sought to determine why a Northern California transit employee opened fire on his co-workers a day earlier, killing nine people, in the latest mass shooting in the United States.
Local authorities have declined to speculate on a motive for the shooting rampage, saying their work at the scene could take several days, assisted by the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives.
The gunfire erupted at about 6:30 a.m. Pacific time on Wednesday as the work day was beginning at a light-rail maintenance yard in the heart of Silicon Valley. The accused gunman shot himself as police closed in on him minutes after he started firing, according to Santa Clara County Sheriff Laurie Smith.
The attack was the latest of at least nine deadly U.S. mass shootings in the past three months, including a string of attacks at Atlanta-area day spas in mid-March and a rampage days later that killed 10 at a Colorado supermarket.