William Denson graduated from the US Military Academy at West Point in 1934 and attended Harvard Law School. He returned to West Point to teach law from 1942 until 1945. In January 1945, Denson accepted the position of Judge Advocate General (JAG) in Europe and was assigned to US Third Army headquarters in Germany. He took part in more than 90 trials against Germans who had committed atrocities against downed American pilots. In August 1945, Denson became chief prosecutor for the US government at the Dachau concentration camp war crimes trial. He was also asked to serve as chief prosecutor for a series of other concentration camp trials, including Mauthausen, Flossenbürg, and Buchenwald. These trials came to an end in early 1947, and Denson returned to the United States.
When you try a number of people at one time -- and you may wonder why we tried so many at one time. We had the 61 there in Mauthausen, we had 40 in Dachau, 45 in Flossenbürg, and 31 in Buchenwald. We had to have representatives out of every phase of operation of the camp, otherwise it would be only part of a picture that we were trying to establish by evidence. And it was important that we established the criminality of the operation of each one of these camps in every one of its phases. Because the charge that we were making was that each of those individuals that sat in that dock as an accused either aided, abetted, participated in the common design of subjecting these individuals to beatings, killings, tortures, starvation, and death. So it was important to have representatives out of each phase of operation. And in that way the court could make a finding that it was a criminal operation in its entirety.