This qualitative case study examines the way school officials implemented the U.S. Secret Service and Department of Education’s principles for threat assessment with a specific student of concern, who underwent a threat assessment and later shot and killed a classmate and himself on school grounds. The data came from deposition testimony from 12 school and district staff familiar with the student and the case and more than 8,000 pages of school, district, and law enforcement records. The findings suggest that district and school officials need to monitor the implementation of the threat assessment process with students of concern. Specifically, the threat assessment team should include 4 to 5 members from multidisciplinary perspectives; team members should complete a comprehensive threat assessment training program; threat assessed students should receive regular check-ins and support; and districts and schools should use an empirically validated threat assessment tool. Finally, educators should consider relying on a continuous improvement model to monitor implementation of threat assessment principles and procedures.