(covers information from several alternate timelines)
A war criminal was someone who was accused of committing a war crime.
In approximately 3074, all of the Kyrian evidence showed that The Doctor was a war criminal. The Kyrian reconstruction of the USS Voyager as the warship Voyager inside the holoprogram The Voyager Encounter was based on a partial, badly corroded schematic found in the Cyrik Ocean. (VOY: "Living Witness")