Sachsenburg authorities issued periodic behavior reports, but often they were just a sentence or two. "G. is a worthless subject and an irresponsible person. He would not be harmed by undergoing a really long upbringing in the camp. He is an example of the need for such camps," said one typical report.

The ITS has 17 files on Sachsenburg, each containing several hundred such reports.

Sachsenburg was an abandoned four-story textile mill, renovated in May 1933 to serve as a "protective custody" facility for dissidents such as Jehovah's Witnesses, outlawed in 1935 because they were among the most obstinate opponents of the Nazi regime, refusing to sing the anthem, give the Hitler salute, respond to the military draft or vote in elections.

In a series of reports over several years, one prisoner is repeatedly denounced as a "stubborn ... Bible student," who tried "to promote his Biblical verses through the hammer and sickle and the Soviet star." Though it did not specify, the wording suggested that the inmate was a Witness apparently trying to convert his communist prison mates.

Before being released, prisoners had to sign a declaration that they would never speak against the Nazis and would report anyone who did. "I will not ask for any compensation," the pledge concluded. "I have not been forced to make this declaration."

The ITS files will be a boon to the researchers in Washington, who are compiling a seven-volume encyclopedia of all known sites where "undesirables" were detained, tortured, put to work or killed. The first volume is in the final editing stage — probably too late to take advantage of the Bad Arolsen archive.

Project director Geoffrey Megargee said the museum team gathered fragmentary evidence from different sources to assemble the list.

"Most historians didn't have a grasp of the scope of the whole universe of camps and ghettos," he said. "Each of them knew their own little slice."

When they began work six years ago, Megargee said the researchers estimated 5,000 to 7,000 sites existed. "Based on our research, it is now clear that there were over 20,000 such sites in Germany, in German-occupied territories and in the states allied with Nazi Germany," he said.

Steven Katz , director of the Elie Wiesel Center for Judaic Studies at Boston University who is not connected with the project, said the encyclopedia will be "enormously useful." Though it will have few surprises for scholars, others using it as a reference tool "will be astonished at the scope of the Nazi enterprise" and the collusion of German industry, he said.