Evidence gathered by Crisis Group shows that there are reasonable grounds to believe the Sri Lankan security forces and LTTE committed war crimes during the final stages of the conflict and that the violations during this period were worse than at any other time during the long civil war. The scale of civilian deaths and suffering demands a response. Peace in Sri Lanka requires some measure of justice. Even if this takes time, future generations will almost certainly demand to know what happened in the Vanni from January to May 2009