Robert Berchtold allegedly convinced other children he abused that they had been abducted by aliens according to the woman behind Abducted in Plain Sight, who has revealed several shocking details were left out of the documentary.

The Netflix hit tells the bizarre true story of how 12-year-old Jan Broberg was abducted twice by family friend Berchtold who had sexual encounters with both her mother and father, married her in Mexico and brainwashed her in to believing she had been abducted by aliens and could save the alien race by having a baby with him.

Filmmaker Skye Borgman admits in a new interview that she was skeptical about victim Jan Broberg's story surrounding her kidnapping and thought it could have been made up as a coping mechanism for Stockholm Syndrome.

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Robert Berchtold allegedly convinced other children they could save the alien race by having sex with him. He's pictured with victim Jan Broberg

The Netflix filmmaker thought Jan Broberg's (pictured) story surrounding her kidnapping could have been made up as a coping mechanism

The woman behind the documentary said she's often asked if the victim's late father Bob (right) had other sexual encounters with pedophile Berchtold. Mother Mary Ann is pictured left and Jan Broberg is second left

Borgman heard stories of others who didn't want to appear on camera while researching the Netflix film and they matched up to what Broberg has claimed. Broberg told how Berchtold would play her creepy recordings on a cassette player from the 'aliens'.

'I constantly questioned if this had really happened,' Borgman told Vanity Fair. 'Then, while we were working on the film, one of Berchtold's other alleged victims reached out to us and told us a story about him using this alien psychology and saying, "You're a princess from a different planet."

'He used this whole alien story on her, and that was the moment for me when I thought, "Oh my gosh, it's real. He did it".'

The cinematographer believes the kidnapper played off UFO news being popular in the media during the 1970s when Berchtold met the family. But he also had the upper hand due to what took place between himself and Broberg's parents.

As well as continuing an affair with Broberg's mother Mary Ann, while proclaiming he wanted to marry the woman's daughter, there was an incident in a car where he convinced the girl's father Bob to stimulate his genitals using his hand.

Abducted in Plain Sight filmmaker Skye Borgman (left) heard stories from other accusers

The stories matched what Jan Broberg said about being kidnapped and taken to Mexico by her captor aged 12 in the 70s

Desperate to keep the sexual encounters a secret, the victim's parents say they felt helpless when their child was snatched.

Borgman was reluctant to question the father about the details of which she found while going through legal documents, but he volunteered the information.

She explained: 'I think Bob realized that it was a critical element to the story, and how [Berchtold] was able to get into their family this way so seamlessly.'

Broberg was taken a second time and attended a private school in LA. She is pictured age 13 in January 1976

The filmmaker said although Bob – who passed away in 2018 - opened about the car incident in the documentary, a detail that was not in the book, he did not address whether his relationship with Berchtold continued.

'We certainly couldn't find any indication that it continued,' Borgman said, adding that she is often asked whether it did and is curious herself.

'I'm not sure that it matters if there was or if there wasn't, because it was this one indiscretion that really gave Berchtold the ammunition he needed to blackmail the head of the household. One time or more than that, the deed was done, and the ramifications of that were set in motion.'

Two years later Broberg was abducted again by Berchtold, this time going missing for 100 days when she was 14 years old.

Berchtold enrolled her in a Catholic girls' school, posing as her father to try and keep her family and the authorities away before she was eventually tracked down and returned home.

Left out of the documentary was an incident where Mary Ann met with Birchtold in a parking lot. The alleged gathering allegedly involved a gun and the woman's brother was present.

The filmmaker had to chop many riveting details for streamlining purposes.

Borgman revealed riveting aspects had to be cut from film including an alleged incident involving Berchtold (center with Jan Broberg), mother Mary Ann (right), her brother and a gun

The documentary, which was three years in the making, consists of reenactments of the events alongside talking-head interviews with the family of the victim, Berchtold's brother and an FBI agent assigned to the case.

The bizarre details of the case have shocked viewers but the kidnapper's brother still wanted to represent him in the documentary since no other family members would.

Berchtold took his own life in 2005 after a court meeting with the victim.

'It's something I think about a lot—that sibling love and how strong that is,' Borgman said about his brother Joe. 'I think that comes out a lot with Joe, that he loves his brother, even though his brother was a pedophile, and I think those two things really are conflicts in him.'