Editor’s Note: Warning: This story contains spoilers about the film.

CNN  — 

“Three Identical Strangers” tells an astonishing story, and the saga is even bigger than what’s seen on screen.

The CNN Films documentary, directed by Tim Wardle, follows a set of triplets who were intentionally separated and then monitored for a secret scientific study. Yet the path to make “Three Identical Strangers,” and what happened after it was released, is almost as twisty as the film itself.

Here are five things you may not know about the documentary:

1. There was a long fight to get access to sealed study records - but they didn’t end up in the film.

As the film explains, triplets Robert Shafran, Eddy Galland and David Kellman were separated at birth by an adoption agency called Louise Wise Services. They were placed into different homes, and their adoptive families had no clue their sons had been born with siblings.

The brothers, along with other multiples who were separated, were then unknowing participants in a yearslong study by child psychiatrist Dr. Peter Neubauer. The results of the study, which examined the question of “nature vs. nurture,” were never published, and the study’s materials are being kept under seal at Yale University.

Now those files aren’t as hidden as they once were. As they were making the documentary, the “Three Identical Strangers” team helped the brothers fight for access to their records.

“We were driven by the injustice on the behalf of the brothers,” director Wardle says. “(Producer) Becky (Read) spent nine months working with the brothers to access the material … files and footage that should rightfully be theirs.”

After months of dogged pursuit, the brothers received nearly 11,000 pages of records, information that hadn’t been seen in decades.

The reason you don’t see more of this material in the film is because it was released after the film was finished, and the team didn’t think the heavily redacted documents would add much to the story.

“There’s a huge amount of personal stuff in those records that are private for a reason,” Read says. “To access their records for the first time in years … that, I think, has been an accomplishment to them. To have some sense of ownership of this after having no control for many years over how their lives were orchestrated.”

2. Those unsealed records included video of the experiment.

The brothers talk candidly in the documentary about what it was like to be studied, completely unaware that the tests they were being given were not part of a routine child development study.

“I remember from a very young age, people would come to the house, usually a young man and a young woman, and they had me taking tests,” Kellman says in the documentary. “I remember the filming more than anything else. … Every single time they came they filmed.”

When the brothers won access to their study records, they found hours of video from those visits. They’ve shared some of that material here.

three id strangers study footage 1
Unseen study footage from 'Three Identical Strangers'
03:34 - Source: CNN

“The footage is like a time capsule, measuring these boys’ lives kind of year by year,” Wardle says. “I think for the brothers, watching the footage for the first time was an incredibly emotional experience. … They’re seeing their whole childhood play out.”

3. Everyone was nervous the film would get pulled.

The filmmaking team knew going in that telling this story was going to be a challenge. They first needed to earn the trust of the brothers, and then they needed to track down the truth about a study so deeply buried that other projects had been shut down, Wardle and his team say.