torture, and that Abu Zubaydah had told investigators that, contrary to what had been revealed previously, "he had been waterboarded at least 10 times in a single week and as many as three times in a day". Shortly before the end of Bush's second term, news media in other countries were opining that under the United Nations Convention Against Torture, the U.S. is obligated to hold those responsible to account under criminal law. On 20 January 2009, Manfred Nowak—the United Nations Special Rapporteur on torture and other cruel, inhuman or degrading treatment or punishment—stated that following the inauguration of Barack Obama as president of the United States, George W. Bush had lost his head of state immunity; Nowak opined that under international law, the U.S. was mandated to start criminal proceedings against all those involved in violations of the UN Convention Against Torture. Law professor Dietmar Herz asserted that under U.S. and international law, Bush was criminally responsible for adopting torture as interrogation tool. United States law and regulations The United States Supreme Court in Sosa v. Alvarez-Machain, said that the Universal Declaration of Human Rights "does not of its own force impose obligations as a matter of international law." However, the United States has a historical record of regarding waterboarding as a war crime, and has prosecuted individuals for such practice in the past. In 1947, during the Yokohama War Crimes Trials, the United States prosecuted a Japanese civilian who had served in World War II as an interpreter for the Japanese military, Yukio Asano, for "Violation of the Laws and Customs of War", asserting that he "did unlawfully take and convert to his own use Red Cross packages and supplies intended for" prisoners, but, far worse, that he also "did willfully and unlawfully mistreat and torture" prisoners of war. The charges against Asano included "beating using hands, fists, club; kicking; water torture; burning using cigarettes; strapping on a stretcher head downward." The specifications in the charges with regard to "water torture" consisted of "pouring water up [the] nostrils" of one prisoner, "forcing water into [the] mouths and noses" of two other prisoners, and "forcing water into [the] nose" of a fourth prisoner. Asano received a sentence of 15 years of hard labor. Following the September 11 attacks, several memoranda, including the Bybee memo, were written analyzing the legal position and possibilities in the treatment of prisoners. The memos,