A scene from the new documentary “Three Identical Strangers.” (Courtesy of the Sundance Institute)

[Note: This story contains film spoilers.]

PARK CITY, Utah — A Sundance movie has taken aim at a prominent East Coast charity, putting the group on the defensive over allegations of stealth experiments on humans.

The documentary, “Three Identical Strangers,” says the Jewish Board of Family and Children’s Services has not made amends for a study that separated identical siblings and conducted secret research on them in the 1960s and 1970s.

The subjects of the film have demanded the release of records from the study, an apology and even compensation, all of which they say have not been offered.

“It was cruel; it was wrong,” David Kellman, a triplet separated at birth from his brothers Bobby Shafran and Eddie Galland, told The Washington Post at the festival this week.

Added Shafran, sitting next to him: “I think the first thing [the Jewish Board] should have done once they became aware of this movie is reunite any twins still surviving and advise those who’ve been deceased, just so they can know who they are. And [the Jewish Board] still never admitted what they did, never said ‘I’m sorry,’ let alone offered any recompense.”

As the country’s most prominent film festival winds down Sunday, it leaves behind a number of films that will make a lasting cultural impression. But one of the movies that might have the biggest news impact is British director Timothy Wardle’s “Strangers,” which on Saturday won a special jury prize for storytelling.

The documentary, which had its final showing at the festival this weekend, tells the story of New York triplets born in 1961 and placed with three local families by the now-defunct Louise Wise Agency as part of a study by the Child Development Center, which would later merge into the Jewish Board.

The boys never knew of one another’s existence until they were 19, when a coincidence at a college in rural Sullivan County reunited two of them, Galland and Shafran. Kellman was reconnected with them soon after when he and his adoptive mother saw news coverage and realized that he was their identical sibling.

“It was the first day of many days in the Twilight Zone,” Kellman said.

“I know a lot of people feel different or strange,” Shafran said. “But for me it was like I had something missing all my life. And when I finally got to school that day [at 19], it was like I was given the instruction manual.”

The three would dine out on the events, making appearances on “The Phil Donahue Show” and in the 1985 Madonna movie “Desperately Seeking Susan.” They would eventually even open a restaurant together named Triplets.

But the story would take a more sinister turn. It turns out that the brothers weren’t split up because the adoption agency wanted to ensure more families received babies, as Louise Wise representatives first suggested to the parents after the boys’ reunion.

Instead, they were part of a secret study conducted by the Austrian-born psychoanalyst Peter Neubauer, who ran the Child Development Center.  As part of Neubauer’s research, the triplets, along with as many as a dozen more sets of identical siblings, were surreptitiously split up and placed with families of different socioeconomic backgrounds, then raised separately so that Neubauer’s team could study the effects of nature and nurture. No one told the adoptive parents their children had identical siblings.

Researchers over the following years were regularly sent to adopted children’s homes to test the children, then reported back to the psychoanalyst. They never revealed to parents the true purpose of their visit or that their child’s identical sibling was often living just a few miles away.

Learning as adults what had happened to them, the brothers said, shook them; Shafran compares it to the Nazis’ social experiments.

The long-term toll the separation took on all three was potentially deep, they said. Galland committed suicide in the 1990s, a possible victim of a hereditary mental illness the two other brothers say was withheld from them.

Although many of the people involved with Louise Wise at the time are gone, Shafran and Kellman allege that there haven’t been nearly enough efforts made by the Jewish Board’s current administration to take responsibility for the organization’s historical involvement with the study.

“It’s not like it happened a long time ago — it happened in modern times,” Kellman said.

“And it’s not like we didn’t have great parents — we did,” Shafran said when told that if all three were placed together, two of them would have had different parents. “But they can’t play God and they did. And for that they should do something,” he said, underscoring his hope for an apology and monetary compensation.

The Jewish Board of Family and Children’s Services, commonly known as the Jewish Board, employs more than 3,000 people and provides services in areas including mental health, early childhood development and domestic violence. The nonprofit organization is nearly 150 years old, and as of 2014 had a budget in excess of $200 million.

Louise Wise ceased operations in 2004 and its records were transferred to a New York adoption center known as Spence-Chapin. But Neubauer’s sealed study, which has long been housed at Yale University, was not released, and requests over the years by its subjects to unseal it were rebuffed.

After the completion of the film, Wardle said, some of the thousands of pages of the study were made public but they were raw and heavily redacted.

“It really wasn’t very useful,” Wardle said. “You didn’t really learn that much from them.”

While Kellman and Shafran say the release of the full study won’t undo the pain of growing up separately — in a working-class and upper-middle-class home respectively — at least it will reveal what their struggle was for.

“It would help us to know what came out of it,” Kellman said. “It would help us if we knew the study may have even done some good.” Neubauer died in 2008.

The Jewish Board did not participate in the movie, fearing interview quotes would be taken out of context, according to a person familiar with the group’s plans who was not authorized to speak publicly on its behalf.

Asked about the allegations made by the film and its subjects, a Board spokeswoman released a statement to The Post.

“The Jewish Board does not endorse the study undertaken by Dr. Peter Neubauer, and is appreciative that the film has created an opportunity for a public discourse about it,” it said. “For many years, The Jewish Board has been, and will continue to be, committed to providing individuals identified as part of the study access to their records in a timely and transparent manner. To date, we have provided records to all individuals who were subjects of the study who have sought them. Because of confidentiality laws, as well as the recognition of the enormous human impact of this study, access to records has been extremely narrow, to these individuals. We hope that the film encourages others to come forward and request access to their records.”

It added, “The Jewish Board had no role in the separation of twins adopted through Louise Wise.”

Others affected by the issue are also spoken of in the film. Paula Bernstein and Elyse Schein, identical twins raised separately, were also unwitting participants in the Neubauer study and learned of each other’s existence as adults; the two wrote a book together. The acclaimed journalist Lawrence Wright included material about the incidents in his book “Twins.”

It wasn’t easy to get the movie made. Wardle alluded to several television-film attempts that were made before, and said he believed they didn’t move forward because of legal pressure.

“Strangers,” which was partly financed by CNN, will air on the network this year. The “I, Tonya” distributor Neon bought theatrical rights at Sundance, ensuring the story will continue to gain exposure.

The filmmakers and subjects say they hope the attention will move the board to heal the rift the study caused.

“They can’t give us back our childhoods but they can find ways to show us they’re sorry,” Kellman said.

At a Sundance screening, Wardle turned to the brothers sympathetically. “You still haven’t gotten the answers you want,” he said. “You still don’t have the truth.”