Advice at the following link, originally prepared by the US ATF, provides a good basic analysis of the problem and presents proactive and reactive steps to be taken to manage such situations.
Bomb Threats and Physical Security Planning
Bomb threats and physical security planning is one of the many subjects covered during the forthcoming university-accredited Security Management Stage 1 Course, 17-28 November. Attended by hundreds of security manager delegates, the course is the most popular of its kind in the world, and constitutes the first step en route to the MSc Work Based Learning (Corporate Security Management) from Middlesex University.
For details click in the following link http://www.arc-tc.com/pages/university_acredited_sm.asp#sm1 or contact Janet.