The postwar judgment of Nazi bigwigs at Nuremberg is an important piece of history, as is the trial of Adolf Eichmann in Jerusalem in 1961. But a third judicial proceeding, brought by German prosecutors and held in a German court presided over by German judges, has largely been forgotten.

This extraordinary trial, spanning 20 months, considered the cases of 22 SS members who’d helped run Auschwitz. The biggest fish was the second in command, camp adjutant Robert Mulka. The other names were even less familiar, although they were well known to survivors as cruel and willing participants in mass murder.

In the early 1990s, a German public television station produced a three-part, three-hour program to commemorate the approaching 30th anniversary of this landmark event in Germany’s path to acceptance of responsibility for the Holocaust. This invaluable documentary, “Verdict on Auschwitz: The Frankfurt Auschwitz Trial 1963-1965,” received a belated and very limited American theatrical release earlier this year. It has recently been released on DVD by First Run Features, and it is well worth seeking out.

The three parts of the film correspond to the investigation, the trial and the verdict. In the first hour, filmmakers Rolf Bickel and Dietrich Wagner provide fascinating background on the diligent and courageous work of local prosecutors that led to the capture of the defendants, who were anonymously ensconced in steady, low-profile jobs outside of urban centers.

The filmmakers combine television and newsreel footage from the early ’60s with pithy, no-nonsense narration. They also include new interviews with Hessian attorney general Fritz Bauer and Hermann Langbein, former secretary of the International Auschwitz Committee, whose memories and perspectives 30 years after the trial were remarkably crisp.

The aesthetic of “Verdict on Auschwitz,” especially in the other two chapters, is simple, straightforward and profoundly effective. Bickel and Wagner draw extensively on the original audiotapes of the trial, primarily the dispassionate but devastating testimony of some of the 211 survivors who comprised the majority of the 360 witnesses.

The filmmakers occasionally illustrate these passages with archival film of Auschwitz and contemporary aerial footage of the vast, empty camp, but mostly the camera tracks around an empty courtroom while a disembodied voice describes in precise detail the hell he or she endured.

It may sound prosaic, but the effect is anything but. The witnesses’ words are so mesmerizing that they require no visual enhancement.

And yet, surprisingly, it is not their voices that stick with us but those of Bauer and the other German prosecutors. Perhaps it is because we have heard survivors describe the death camps in other documentaries but have never been exposed to Germans evincing their disgust with the henchmen of the Nazi regime.

As Frankfurt lawyer Henry Ormond declared, “One shudders to think that those on trial here today were regarded as the elite of the German people for 12 years, and saw themselves as such. One is ashamed for the German nation that it accepted such a thing.”

At the same time, the filmmakers are careful to note that the trial was incomplete on one count. The roster of defendants did not include the higher-ups in the SS, who were able to dodge prosecution thanks to their positions of authority in German society.

Nonetheless, the trial was a catalyst for the German people to finally confront their horrific past. It was a major event for the postwar generation, especially, whose parents had been overwhelmingly silent about the war years.

Thirty years later, “Verdict on Auschwitz” provided history and context to yet another generation, the one coming of age in 1993 as neo-Nazis and right-wing groups became more outspoken in the reunified Germany.

The film has slightly different resonance to current Americans. It is an inspiring record of both state-sponsored justice and solid journalism, two things that are in short supply.