At the end of World War II, members of the film unit of the OSS — the Office of Strategic Services, precursor to the CIA — were put to work hunting down every scrap of film footage they could gather about Nazi Germany, the rise of the Third Reich, and the atrocities committed by officials who were to be put on trial at Nuremberg.

The officer that OSS film unit chief John Ford — yes THAT John Ford — assigned the job to was Budd Schulberg, son of pioneering screenwriter, film producer and studio executive B.P. Schulberg. Schulberg and his brother Stuart were sent to the ruins of Nazi Germany to find the filmed “proof” of who and what the Nazis were, film that would be used in court.

The idea, American prosecutor Judge Robert H. Jackson said, was “to convict” those charged “by using their very own words,” preserved in speeches, at rallies, and captured for posterity by German filmmakers and Nazi propogandists.

“Filmmakers for the Prosecution,” made for French TV under the title “Nuremberg: des images pour l’histoire,” is a documentary recounting that search, the efforts by the Germans to destroy much of the footage in the weeks and months after the war and before the trials, and the filmed evidence the Schulbergs and others found and assembled for the court to see.

But as that material, which includes heartbreaking and damning samples of the footage shown in court, only added up to a little over half an hour of screen time, “Filmmakers” director Jean-Christophe Klotz, gets into future producer Stuart Schulberg’s efforts to film the trial, make an official, government-backed “Lessons from Nuremberg” documentary and get it shown in an America that was rapidly sucked into a Cold War as the trials wound down and lost interest in punishing the villains of the last war.

So like the “Filmmakers” themselves, Klotz, working with film producer and former First Run Features co-founder Sandra Schulberg (that’s three generations in the biz, for those keeping “Nepo Baby” count) got lost in a bit of “mission creep” in recreating this “Monuments Men” moment of movie business folks in the military gathering evidence for the trial of those who committed “the greatest crime in history.”

There’s wrenching footage of “the first attempt at gassing” human beings, Germans filming their efforts to mass murder inmates from a camp for the mentally and physically-disabled using automobile exhaust in an airtight barn. We see grainy 8mm images of a Nazi pogrom, rounding up villagers in Ukraine.

Budd Schulberg was already screenwriter, and a famous novelist thanks to his scathing “What Makes Sammy Run?” The film business insider in him informed what he was seeing in the hours and hours of footage, including German soldiers carrying out mass burials at death camps. We see portions of a speech he gave at the Justice Robert H. Jackson Center, where he noted an image that brought home the scale of the crimes committed, up and down the German Army hierarchy and the Nazi chain of command.

As Schulberg saw footage of those emaciated bodies pushed down a slide into a lime pit where scores were already piled up, the cameraman shooting that scene catches another soldier-cameraman down in the pit, having crawled there to get “good shots” of the murdered bodies sliding down at him.

That’s about as inhuman as it gets.

The most interesting portion of this film is footage itself, much of it quite grim, and the search for these German cannisters of film, seeing snippets of how it was gathered up and edited by editor, actor and later director Robert Parrish, among others (mentioned in a letter of Stuart Schulberg’s read in voice over) and was used in the Nuremberg court.

It’s one thing to rely on witnesses and dry mountains of detail-obsessed German government paperwork to convict mass murderers. Jackson’s gamble on making the motion picture evidence the Germans themselves provided was a tipping point, showing this or that “not a member of the Nazi Party” or “not in the inner circle” defendant singled-out for a close-up in Leni Riefenstahl’s “Triumph of the Will.”

Heinous crimes that the German government ordained, condoned and then paid to film were exposed in front of a court filled with mostly-doomed defendants, lawyers and judges and hundreds of members of the press.

The frustrating efforts of the nascent filmmaker Stuart Schulberg to make his “Nuremberg” under tight court restrictions and navigate Cold War politics to get the film finished while losing a race against a Russian filmmaker who got the Soviet version of the historic trial out first are interesting, but only as an afterthought. His “trial” film, finished and 1948 and restored over a dozen years ago by Stuart’s daughter Sandra, is historically important, but dry. Stuart Schulberg would go on to a career producing films and TV shows, mostly documentaries.’Sandra, is historically resonant, but dry. Stuart Schulberg would go on to a career producing films and TV shows, mostly documentaries.

“Filmmakers” makes the case that these two brothers shaped the way the world viewed the atrocities of World War II thanks to their gathering of filmed evidence and the way they presented it, the horrific images that sent Nazi leaders to the gallows. That seems somewhat narrow, an overreach neither brother claimed while they were alive, even though — oddly — they filmed “recreations” of the hunt for film cans and the two of them, and their editors, looking at the footage. What was that for, a documentary about them making a documentary?

That looks self-Schulberg serving, and probably isn’t something the brothers themselves would have condoned, which is why we’ve never seen it before now. But Stuart’s daughter produced “Filmmakers,” so here it is.

Rating: unrated, disturbing images of the violence and mass murder of the Holocaust

Cast: Sylvie Lindeperg, Stuart Liebman, Victor Barbat, Niklas Frank, Budd Schulberg and Sandra Schulberg

Credits: Directed by Jean-Christophe Klotz, based on a monograph by Sandra Schulberg. A Kino Lorber release.

Running time: 1:00