Today terrorists usually work in network forms to conduct attacks. Terrorist networks remain active and can still function even after being severely damaged by authorities. Analyzing terrorist networks from a dynamic point of view can provide insights about the mechanisms responsible for the survival of terrorist organizations. This paper studies the dynamics of a major international terrorist organization over a 14-year period – the Global Salafi Jihad (GSJ) terrorist network. We found that a scale-free topology gradually emerged as new members joined the GSJ network based on operational needs. In addition, since the network has been experiencing member losses while it grows, we also studied the robustness of the GSJ network. We used a simulation approach to examine its vulnerability to random failures, targeted attacks, and real world authorities' counterattacks. We found that authorities' counterattacks have been rather ineffective in disrupting the terrorist network.