Suicide bombers have become increasingly deadly and there is an urgent need for the development of innovative methods to prevent or mitigate the casualties and aftermaths of such a catastrophic event. Performing simulations with variant crowd formations and densities is one approach to better understanding the effects of such an attack. This paper explores and estimates the effects of suicide bombers across multiple crowd formations and their respective densities through a virtual simulation. The ultimate goal of our empirical analysis was to determine the optimal crowd formation as it related to a reduction in the deaths and/or injuries of individuals in the crowd. The modeled crowd formations were based on real-world environments and consisted of a cafeteria, concert hall, mosque, street, hotel, bus, airport, and University campus. Specific simulation inputs are the number of individuals in the vicinity, walking speed of attacker, time associated with the trigger, setting (crowd formation), and the total weight of TNT. Results indicated that the worst crowd formation is a circular one (e.g. concerts), with a 51% death rate, 42% injury rate, thus reaching a 93% effectiveness measure. Vertical rows (e.g. mosques) were found to be the best crowd formation for reducing the effectiveness of an attack, with a 20% death rate, 43% injury rate, reaching a 63% effectiveness measure. Line-of-sight with the attacker, rushing towards the exit, and stampede were found to be the most lethal choices both during the attack and post-explosion. These findings, although preliminary, may have implications for emergency response and counter terrorism. There are number of physical and social variables we plan on integrating into this simulation in the future. These include modeling physical objects (e.g., landscape, furniture, etc.) and psychological variables (e.g., crowd behaviors). There are numerous applications for this simulation, ranging from special event planning to emergency response.