War Crimes Rewards Expansion Act This bill expands the Department of State's rewards program to authorize rewards for providing information leading to the arrest, conviction, or transfer of a foreign national accused of war crimes, crimes against humanity, or genocide as such crimes as defined under the law of an international criminal tribunal, the applicable country, or the United States. Currently, rewards are authorized for information leading to the arrest, conviction, or transfer of a foreign national accused of such crimes only as defined under the statutes of the relevant tribunal.