Here's a recent release from Georgetown University Press: 
Human Rights after Hitler: The Lost History of Prosecuting Axis War Crimes (March 2017), by 
Dan Plesch (University of London). A description from the Press:
 Human Rights after Hitler reveals thousands of forgotten US 
and Allied war crimes prosecutions against Hitler and other Axis war 
criminals based on a popular movement for justice that stretched from 
Poland to the Pacific. These cases provide a great foundation for 
twenty-first-century human rights and accompany the achievements of the 
Nuremberg trials and postwar conventions. They include indictments of 
perpetrators of the Holocaust made while the death camps were still 
operating, which confounds the conventional wisdom that there was no 
official Allied response to the Holocaust at the time. This history also
 brings long overdue credit to the United Nations War Crimes Commission 
(UNWCC), which operated during and after World War II.
Human Rights after Hitler reveals thousands of forgotten US 
and Allied war crimes prosecutions against Hitler and other Axis war 
criminals based on a popular movement for justice that stretched from 
Poland to the Pacific. These cases provide a great foundation for 
twenty-first-century human rights and accompany the achievements of the 
Nuremberg trials and postwar conventions. They include indictments of 
perpetrators of the Holocaust made while the death camps were still 
operating, which confounds the conventional wisdom that there was no 
official Allied response to the Holocaust at the time. This history also
 brings long overdue credit to the United Nations War Crimes Commission 
(UNWCC), which operated during and after World War II. 
From the 
1940s until a recent lobbying effort by Plesch and colleagues, the 
UNWCC’s files were kept out of public view in the UN archives under 
pressure from the US government. The book answers why the commission and
 its files were closed and reveals that the lost precedents set by these
 cases have enormous practical utility for prosecuting war crimes today.
 They cover US and Allied prosecutions of torture, including “water 
treatment,” wartime sexual assault, and crimes by foot soldiers who were
 “just following orders.” Plesch’s book will fascinate anyone with an 
interest in the history of the Second World War as well as provide 
ground-breaking revelations for historians and human rights 
practitioners alike. 
Lots more information is available 
here, at the book's website.