Facebook headquarters cleared after false threat

Menlo Park, California: Police flooded Facebook's headquarters in Northern California to investigate a threat they later found wasn't credible.

Menlo Park police Commander Dave Bertini says Facebook's campus was locked down Tuesday night after San Francisco police passed on a report of a threat shortly after 7 p.m.

Bertini says the threat was found to be unsubstantiated and not credible, and would not give further details.

The area was declared safe, and employees were allowed to leave about 8:30 p.m.

More than 6,000 people work for the social media giant, but it wasn't clear how many were at the headquarters at that hour.