A bomb threat prompted authorities on Dec. 11 to evacuate a building at the Silicon Valley headquarters of Facebook Inc , police said, but gave the “all clear” after an hours-long search turned up no sign of a device.
The New York Police Department had received an anonymous tip about a bomb threat regarding Facebook’s campus in Menlo Park, California, and alerted local authorities at about 4:30 p.m. local time, a spokeswoman for the Menlo Park police said.
