Final Report and Findings of the Safe School Initiative: Implications for the Prevention of School Attacks in the United States [open pdf - 2MB]
This document, the Safe School Initiative's final report, details how the Secret Service and U.S. Department of Education studied school-based attacks and what they found. It is clear that there is no simple explanation as to why these attacks have occurred. Nor is there a simple solution to stop this problem. But the findings of the Safe School Initiative do suggest that some future attacks may be preventable, if those responsible for safety in schools know what questions to ask and where to uncover information that may help with efforts to intervene before a school attack can occur.
United States Secret Service: http://www.secretservice.gov/