Denson was a 32-year old graduate of the West Point army academy and Harvard Law School when he was sent to the Judge Advocate's Office in Europe in 1945, and assigned as chief prosecutor for the trials which were soon to start at Dachau covering crimes committed at Buchenwald, Matthausen, Flossenberg and Dachau itself. Technically the four were "mere" concentration camps, rather than Vernichtungslager, or extermination camps, such as Auschwitz or Treblinka. But the wickednesses committed there were scarcely less egregious.
Among those prosecuted by Denson was August Eigruber, a Nazi Gauleiter in upper Austria whom he later described as "one of the most arrogant defenders I have ever encountered". Even from the scaffold, as the noose went around his neck, Eigruber shouted "Heil Hitler". The most famous defendant with whom he dealt however was Ilse Koch, dubbed the "Beast of Buchenwald" for her habit of personally selecting prisoners for sadistic beatings and torture which often killed them, and accused of having lampshades and photograph albums made of tattooed human skin.
Because she was pregnant when she went for trial, the 40-year-old Koch was sentenced to life imprisonment rather than death for her crimes against non-Germans. To Denson's declared disgust, her term was reduced in 1947 to only four years by General Lucius Clay, then the senior US official in occupied Germany. However she was resentenced to life by a German court for crimes against German citizens, and eventually committed suicide in 1967.
In a 1990 interview, Denson recalled how at first, although hardened to the horrors of war, he could not believe what he was hearing from camp survivors:
I thought here were some people who had been mistreated in the camps and were seeking revenge, and that they were real-
ly doing a job drawing on fantasy rather than reality. But when I questioned witnesses, and they recounted substantially the same things, then I knew the events had occurred, because these people did not have a chance to get together and fabricate their stories.
Those who were in the dock struck him as having come from fairly normal backgrounds: but, Denson said, exposure to violence merely generated more violence; experience of atrocity merely raised the threshold of future atrocity. Of the 177 people he prosecuted, only four were acquitted, and 132 were sentenced to death. It was the highwater mark for war crimes trials in Europe. A dozen more tribunals would sit in Nuremberg, but of the 185 who appeared before them, just 25 were sentenced to death.
In 1948 Denson returned home from Europe to become chief litigator for the Atomic Energy Commisson in Washington - only to find himself representing the AEC in the trial of Julius and Ethel Rosenberg, who were convicted and executed in 1953 for passing atomic secrets to the Soviet Union. He then became a partner in a New York law firm, specialising in patents and copyright, before ending his career with Melzer, Lippe, Goldstein, Wolf and Schlissel of Mineola, Long Island.
William Denson, lawyer: born Birmingham, Alabama 1913; married 1950 Constance von Francken-Sierstorpff (one son, two daughters); died Lawrence, New York 13 December 1998.