California gunman who killed nine had warned ex-wife he would shoot workmates

A emergency crew at the scene of the shooting in Santa Clara, California (Noah Berger/AP)

An employee who gunned down nine people at a California rail yard and then killed himself as law enforcement rushed in had talked about killing people at work more than a decade ago, his ex-wife has said.

“I never believed him, and it never happened. Until now,” a tearful Cecilia Nelms told the Associated Press on Wednesday following the 6.30am attack at a light rail depot for the Valley Transportation Authority in Santa Clara, near San Jose.