In order to convict and punish individuals charged with genocide, the U.N. prosecutor at the ad hoc War Crimes Tribunal must prove intent as a state of mind. That standard of proof in criminal trials against individuals differs from the civil standard applied by the ICJ in reviewing a state's claim for reparations against another government. In state vs. state civil proceedings intent can be deduced from acts without proving a guilty mind.
General principles of nations provide a source for the lower standard in civil proceedings. In the U.S., criminal guilt must be established by proof beyond a reasonable doubt while civil liability is based on a less demanding standard of proof--the preponderance of the evidence. Similarly, Chinese law requires an employee living above his known income to identify the source.