Peter Black describes the role of historians in researching war crimes cases for OSI

When the OSI hired full time historians to work on the cases that were floating around -- and the OSI inherited 300, approximately 350 from the INS, many of which had been kicking around since the 50s and the 60s, uninvestigated particularly after the Artukovic fiasco in the mid 50s -- the historians in their search for documentation relating to the place or places where the defendants served, and relating to the units in which the defendants served, came across rosters of individuals, many of them with birth dates, and birth places, and early on, beginning even in 1980, the investigators were running postwar lists developed by American authorities, of war crimes suspects, through the Immigration and Naturalization Service to see whether matches had taken place, or whether there were hits, we called them hits, that an individual of the same name and the same birth year at least, often the same birth date, of this war crimes suspect had actually entered the United States on such and such a date. Once we started collecting rosters, this became a fairly large operation. We were the first and only unit outside of the Federal Republic of Germany and the Soviet Union to investigate in this way. And so we began, I would say certainly by 1982, 1983, 95 percent if not better of our cases originated this way. The historians would gather rosters in the course of one investigation in order to identify other members of that unit, in part as potential sources for witnesses, and in part as potential evidence for that particular investigation and then would run those names through the Immigration and Naturalization Service to determine whether these people came to the United States, and if we could determine whether they came to the United States then they either became witnesses themselves that we wanted to talk to about their comrades, or they became, and in most cases they did become, subjects.