In Peacock’s A Friend of the Family, Jake Lacy plays Bob “B” Berchtold, a man who befriends a Midwestern Mormon family in the 1970s, only to kidnap their young daughter Jan not just once, but twice. It would be an unbelievable story if it weren’t true: Jan Broberg’s story was previously chronicled in the 2017 documentary Abducted in Plain Sight.

For Lacy, playing a kidnapper and pedophile was an emotional challenge for the actor, particularly given the ages of his victim: Jan was 12 and 14 when she was kidnapped. Hendrix Yancey, now 11, and Mckenna Grace, 16, play Jan at the different ages, while the real Jan Broberg and her mother, Mary Ann, were often on set as they served as producers on the limited series.

“It’s so selfless for them to say, ‘We want this story told so that people understand what grooming and coercion and manipulation look like,’ ” Lacy tells THR about getting the Brobergs’ blessing. “And understand that we didn’t get to 1985 and this stopped. It’s still widely prevalent today, and it most often happens at the hands of someone you know and love and trust. That’s why it’s so incredibly difficult to talk about and to prosecute.”

The series starts out with the real Jan Broberg sitting in a chair, introducing herself and telling what happened to her.

There were two purposes in doing that. One was to let people know Jan is OK. The story doesn’t end with Jan dying or disappearing. She’s here, she’s vibrant and alive, which I think lets people give over to the story a little more than the complete horror of thinking, “Am I watching the story where this child doesn’t come back?” Also, it’s nearly unbelievable, unless someone says, “This happened.”

Did you feel any trepidation to take on such a sinister role?

No. This isn’t some voyeuristic look at their lives or some tabloid version of a story. We wanted to be authentic and compassionate toward what the experience was like inside this family, inside this community when this wonderful young girl gets taken. … Ultimately, the saving grace for me, and for the production, was that there’s a real purpose in telling this story: Let’s shine a light on what it is to be a victim of both sexual abuse as a child, but also as a family and the people surrounding that, and what it’s like when you’re in the grasp of a predator who’s manipulating and gaslighting and coercing, and how difficult it is to make decisions that from the outside is very easy to say, “That’s a red flag, why did they do that?” But from inside the experience, you feel cornered and trapped and alone. That’s the tool he uses to get what he wants. And he’s very good at it.

What kind of research went into this?

Jan was so wonderful to say, “I’m available.” And I kept her at arm’s distance, somewhat out of fear and somewhat out of needing to create this silo where I had zero emotional connection to real-life Jan Broberg, because Robert Berchtold is obsessed with Jan, but is a void of emotion. It was hard enough to create this and find a way into this role to then also have a personal friendship with Jan. I thought, “I can’t balance those,” and I was wrong. She reached out and left me this wonderful note on the first day of filming, and I think she knew that I was hesitant to reach out to her. The note described a bit of how Berchtold was warm and charismatic and funny and kind, and that was how he wedged himself into the family and gained their trust and how he then got what he wanted. And the back half of the note was saying, like, “I’m OK, I’m in a healthy place, and I’m thrilled you’re doing this, and you have permission to do this role and tell this story as you see fit without being worried.” The level of grace and compassion for someone to offer that to me, who’s just some dumb actor playing this part, when she’s the one who’s actually experienced it, is beyond my comprehension. And from there, I remained creatively at a distance so as to stay in this delusional orbit of Berchtold’s own making, but anytime she was on set, we would eat lunch together and talk. It turns out that it was possible to have an affinity and friendship with her, and also tell this story.

There was a conscious decision made to not show any intimate scenes between Jan and B, yet there are so many uncomfortable scenes. How did you and the two actresses who play Jan establish a safe space?

Jan was creatively involved, and creator Nick Antosca really hammered home [that] we’re not showing the abuse, we’re not casting an 18-year-old actor and then hoping they look 14, and then performing these scenes. He said, “I have no interest in creating that and putting that in the world.” … A long stretch of this story is the Brobergs feeling there’s something horrible happening, and we don’t know what it is. The audience also experiences: “There is something horribly wrong here.” So it works in our favor, creatively and just as human beings, to say, “We’re not doing that.” The production and also the producers on set really [went] out of their way to create this safe, supportive environment, between having a therapist on set, along with changing the scripts that the minors had so that any mention of things sexual in nature were either taken out or were rewritten. An example is, like, there’s a book that B has planted in the motor home, and it’s The Joy of Sex, and Jan finds it. But when we shot with Hendrix, the book we use was titled People From Another Planet. Even the props that are there are not potentially creating trauma for a young person in this environment. And then later, we go back with a hand double and get an insert of the actual book. … Ultimately, it comes down to just two people, and so before and after every take, I’m very low-key, like, “Are you good?”

Was there one scene that was more challenging to film than others?

It’s where we’ve put a trampoline at the house and during the car ride to school, I say, “Don’t mind my boys, they’re tired from all the jumping around,” very low-key planting all these little bread crumbs to get Jan to think it’s her idea to have a sleepover at the house. … And that was the first time that we’d really gone, filming-wise, from how he manipulated the family into being friends. That whole scene takes place in a kitchen, in the dark; it’s very quiet and intimate. It’s the three of us — Lio [Tipton, who plays B’s wife, Gail] and Hendrix and I — in this familial portrait, except that this girl has just been sexually abused. That, to me, is so horrific.

Interview edited for length and clarity.

This story first appeared in the Nov. 21 issue of The Hollywood Reporter magazine. Click here to subscribe.