Ben was born in a small village in the Carpathian Mountains of Transylvania in Romania. When he was an infant, his family moved to the United States. Ben attended Harvard University, where he studied criminal law. Ben graduated from Harvard University Law School in 1943. He joined a US anti-aircraft artillery battalion that was training in preparation for an Allied invasion of western Europe. At the end of World War II in Europe, Ben was transferred to the war crimes investigation branch of the US Army. He was charged with gathering evidence against and apprehending alleged Nazi war criminals. He ultimately became chief US prosecutor in The Einsatzgruppen Case of the Subsequent Nuremberg Proceedings.
What I would do, as a matter of procedure, I would immediately try to seize the records of what had happened in the camp. And every camp had an office, a Schreibstube, writing office. And what I would do is I would immediately go to the Schreibstube and try to find out who was in charge there, what was there, and seize whatever would be relevant for war crimes prosecution. And when I came to the Schreibstube in Mauthausen, uh, there was an inmate there who was a "Schreiber" [who worked in the office], as they called them, uh, and that was a favored position, in fact, in the camp if you would be in the hospital or in the Schreibstube or in the kitchen. Um, and he said, "Oh, I've been waiting for you," and he said, "Come with me," and I recall going out with him to the electrified fence and his digging up a, uh, box of records which he had kept. And, uh, those records, uh, were the records of all of the SS men--the identification cards--who had entered that camp, uh, and who had left the camp. It had their photograph on it. It had their identifying numbers and addresses, date of birth, things of that kind. And he was supposed to destroy each one of those records before a new one was issued or when the man left the camp, and he didn't do that, which meant that every time he saved one of those records--and there were hundreds of them--he put his life in jeopardy. And he was ready to do that, hoping and knowing that one day there would be a day of retribution. And he saved those records for that day. So to me, it was a reflection of human hope and, uh, confidence, and faith, you know, uh, and courage, which was very moving and dramatic for me.