Try them in the International Court, the same court the UN is pressuring the US to allow to have jurisdiction of its soldiers.

New standards for UN troops?
Abraham McLaughlin and Michael J. Jordan, CSM Original Article

Faced with a double-barreled crisis over its inability to forge even a semblance of peace in the African jungles of Congo or prevent its soldiers from sexually abusing civilians there, the United Nations' biggest global peacekeeping operation is undergoing a dramatic makeover. The changes may set important precedents, experts say, for UN peacekeeping efforts worldwide.