Before setting foot on the campus, SWAT team members already knew the safest way to enter the classroom and exactly what they would find once they got inside. Their laptop computers were loaded with a GIS that combines computerized maps of the high school with databases that cover every conceivable detail of the 46-acre campus. The system was developed by PSOMAS, a consulting engineering firm based in Los Angeles. Having the wealth of information the GIS system provides beforehand eliminates the need for physical reconnaissance of the crime scene before going in, greatly accelerating police response time. Upon receiving the call that two perpetrators were holding six hostages in an empty classroom, the SWAT team officers left the police station immediately with just sketchy information about what had occurred. Before reaching the school, their laptops used the GIS program to locate on the map the room where the hostages were being held. Once the team reached the school, the GIS brought up accurate aerial photos of the school overlaid with a map of the campus that showed the exact location of all classrooms and facilities. These tools gave the officers the details they needed for the immediate and effective deployment of resources, such as where to position the perimeter contingent of officers, where the crisis negotiating team should set up, and where the optimum position would be for the immediate-reaction team. Using the GIS, pre-defined scenarios can be linked to provide fast response with vital information on how to handle any type of situation. Other police applications for various police response scenarios are also briefly considered in the concluding section of the article.