Shooter blocked door, screamed before rampage

Police said Shareef Allman, 47, opened fire at the Permanente Quarry, killing two people and wounding at least six others during a morning meeting on Wednesday, Oct. 5, 2011.

October 8, 2011 5:50:50 AM PDT
An hour had passed and three of their colleagues lay dead when surviving workers at a Silicon Valley cement plant heard an ominous voice on a work-issued walkie-talkie: the gunman, who'd fled the bloody scene, was vowing to return.