Twelve years ago this December, the actor Brittany Murphy died under circumstances mysterious enough that lingering questions about her death still overshadow her career. Was she poisoned? Was her slick-haired screenwriter husband Simon Monjack involved? And how do you explain Monjack’s own death five months later, which was eerily attributed to similar causes of Murphy’s passing: pneumonia and severe anemia?

These are some of the questions addressed in HBO Max’s fascinating two-part documentary What Happened, Brittany Murphy?, which premieres Thursday. But the project, from Emmy-winning director Cynthia Hill, focuses equally on Murphy’s life and career, remembering the ebullient actor who first charmed audiences in Clueless and earned accolades for her performances in Girl, Interrupted and 8 Mile. The filmmaker also traces Murphy’s emotional journey—as a woman who suffered a string of professional and personal heartbreaks that left her vulnerable to Monjack, a manipulator whose own mother describes him on camera as being “economical with the truth.”

The film features candid interviews with Clueless director Amy Heckerling and Murphy’s King of the Hill costar and friend Kathy Najimy; never-before-seen video of Brittany as a child actor with a megawatt smile and personality; and heartbreaking footage of Murphy, so drug-addled that she cannot remember her lines, on the set of one of her final movies, Across the Hall. There are also enough bizarre, dark twists about Monjack to fill several episodes of Dateline—and those were only the revelations that made it on camera.

“I feel a little bit conflicted that Simon kind of hijacks Brittany’s story,” says Hill in our conversation. But after viewing What Happened, Brittany Murphy? it is apparent that Monjack did the same when Murphy was alive. “I think that it is a story about power and control—in Hollywood and in relationships—and the damage that things can do to an individual and how things can get lost in that.”

Ahead, the filmmaker discusses her investigation of Murphy, hiring a P.I. during production, and uncovering secrets about Monjack that Murphy, his own wife, wasn’t aware of. [Spoilers ahead.]

Vanity Fair: What led you to make a movie about Brittany Murphy?

Cynthia Hill: Blumhouse approached me with the idea…and I wasn’t sure. I am a casual fan of her work, but didn’t really know too much. Then I dove down the rabbit hole to try to get past all the stuff about her death to figure out who this young woman was. The first thing that was compelling to me is that her life and career had been eclipsed by the mystery around how she died. It just seems so unfortunate that that’s how people refer to her—as this woman who died so mysteriously at 32.

During this phase of getting to know her, who were some of the first people who knew Brittany that were willing to open up to you?

That was difficult. Not a lot of folks wanted to open up initially…I had a list of folks that I wanted to talk to—family members, managers, agents, costars, the ones that seemed to have the closest relationship with her. But we just kept getting no after no after no, and were like, “What in the world?” Even with the Blumhouse clout in the industry, that still didn’t seem to get us very far.

There were folks who were connected to the story that didn’t have as much of an emotional connection to her that we were able to reach. And Andrea Weibel, who works with me, who started out as an investigative reporter and is now a producer with me, she went into the coroner’s office, the pathologist route, and tried to find out all of those kinds of details. She also found her older friends in New Jersey who hadn’t been in touch with her in recent years. They were willing to talk. But most of the folks that knew her in the end, it took a good bit of work to get access to them.

Why do you think people were so reluctant to talk, even though it’s been over a decade since her death?

I think it’s twofold. I think it’s, “What hell is she going to do with this story?” It’s always been treated as such tabloid fodder. So I think they were mistrusting of what the outcome was going to be. And then the other reason, I think, is that there is still a good bit of regret around what happened to her and people feeling some guilt around it…“What could we have done?”

But when you finally landed those interviews—I’m thinking of Amy Heckerling and Kathy Najimy specifically—I was surprised how candid they were with you about Brittany’s struggles. At what point during the process did you get their perspectives?

Those were my last two interviews. But we did do this super fast—from start to finish this took about seven months. I’m not used to having to develop relationships that quickly, especially Hollywood relationships, where I think there’s a lot of mistrust. I think that being from the outside helped me a good bit, because I wasn’t coming to the story with the baggage that comes along with being in Hollywood. As I built relationships, one person would call another on my behalf…and so on. A lot of folks that you don’t see on camera in the doc were willing to speak off the record to help pave the road.

The documentary takes viewers on this emotional journal—what Brittany’s life was like at the beginning to the very end, and all of the emotional struggles along the way. The one constant is Brittany’s mother, Sharon, with whom Brittany was incredibly close. Were you able to get in touch with her?

We tried very hard to connect with Sharon, to the point where I ended up hiring a P.I. to track her down because no one knew where she was. We did locate her, and we hand-delivered a note to her. She didn’t respond, but I did get confirmation that she had received it…I understand she has been mourning the loss of her daughter this whole time…so we had to find surrogate voices because we didn’t have access to her or other close members of her family.

How did you manage to get Simon’s mother, Linda, and brother, James, on camera?

James ended up reaching out directly to us whenever the announcement was made [about the project], saying that they would like the opportunity to speak on Simon’s behalf since he was not present. I think that there was some suspicion or maybe an assumption that Simon would not necessarily be painted in the best light, or at least they wanted the chance to speak for him.

It was fascinating watching those conversations, because Linda doesn’t completely absolve her son of lying to and manipulating people. Can you talk about going into those conversations?

I was assuming there was going to be some loyalty to their family member, but it was interesting to watch her explain some of [Simon’s deceptions] away. One interesting thing she said was that Simon was “economical with the truth.” I have never heard lying put like that before—that’s a very sophisticated way to say he was a liar. But I think they also had a complicated relationship with Simon. James had a very complicated relationship with him. They were not close. From the conversations we had prior to the interview and during the interview, I think James struggled with Simon’s behavior and actions. He would say, “We are not the same person.” To me, that was code for, I don’t approve of what he did…because he kept saying, “We’re not the same.” He wanted to make sure that I was clear about that.

Linda, on the other hand, I felt was in denial about some of the things that had transpired and some of Simon’s actions. But her son is dead and gone, and I’m sure that you want to remember your child in the best possible light.

James’s reactions to some of Linda’s deflections or denials were so telling—he would turn and look at her at times like he could not believe what was coming out of her mouth.

I’m glad you saw that. It’s like his reaction was telling us what she wasn’t.

This is a bit of a spoiler, but you also get an in-depth interview with a former girlfriend of Simon’s, who alleges that she was manipulated by Simon the same way that Brittany was. Even more shocking though, the woman had a child with Simon whom Brittany knew nothing about. How did you find her?

Well, he has another child that we ended up finding on Instagram. We ended up reaching out to her for legal reasons because there was an issue of who has ownership of Simon’s photography. We ended up finding her, and I was communicating with her through other folks to negotiate that. [Sighs.] There was still a lot that we didn’t put onscreen but it became important for us to unpack the story.

It sounds as though he hijacked her life in those final years—between cutting her off from her friends, insisting he work as her makeup artist to keep an eye on her on set…

Yeah. Those last couple of years, he was the one that was there. I’ve spoken to quite a few folks who are not on camera that were really close to Brittany that got cut off from her by him. They would express their concern, and then he would find ways to plant distrust for these people who were friends with Brittany for four years, 13 years, 14 years…he would find ways to put a wedge in there to isolate her.

Getting back to Simon’s children, though—children that Brittany did not know existed. How did you learn about them?

We also reached out to journalists who were covering Brittany, either before she died or after she died, by covering Simon. Sarah Hamill, who worked for People, covered him. I don’t think this made it in the final cut, but when she started writing about him, he called her out of the blue and said, “This is Simon Monjack. I hear that you’re saying nasty things about me,” in his very fancy British accent…he had to find ways to manipulate and control, or try to control. I just think he thought he was smarter than everybody else.

So Sarah led you to this chapter of Simon’s life?

Sarah is the one who put us in contact with Elizabeth [Simon’s ex-girlfriend and mother of one of his children]. Elizabeth had been unwilling to reveal herself or the identity of her son when Sarah was covering Simon. Sarah is no longer working in the industry, and she was like, “Elizabeth might be willing to talk now.”

What do you think made her feel okay about telling her story now?

I can’t speak for her, but I think that she’s been sitting on this story and pain for a long time. [Her and Simon’s son] Elijah just turned 21. So she was able to ask him if he was okay with it. And she felt that he was old enough to make the decision for himself. I think she needed a chance to tell her story to take some of the control back of this narrative that began 21 years ago.

I imagine you reached out to Ashton Kutcher. Were you able to talk to him?

I can’t say.

The documentary includes audio from an interview that Ashton did with Howard Stern when he was dating Brittany. It’s revolting to listen to—and reminds me of the other media coverage we’re revisiting now of female stars in the ’90s. In it, Howard essentially taunts Ashton for dating “the fat chick” from Clueless. Ashton does what he can to defend her, but the damage is done.

It’s one of those things that was so telling of the time and the way actresses were treated. It was like they weren’t even humans. I do think times have changed and things are getting better, but they still aren’t great.

You also uncover this moment in Brittany’s career where she is denied a role because a casting agent says she is “not fuckable.” The documentary makes it seem as though this comment inspired her to completely transform her body…and within a few years, we see Brittany go from a skinny actor to an emaciated actor.

There were a couple moments like that—she did this audition for Coyote Ugly but did not get the part because she was “not fuckable.” I’m just like, What does that mean? No one should be measured that way, and it’s very disturbing that that was acceptable behavior. I’m sure she just did not know how to respond. And what do you do with that? Even the strongest person who has the thickest skin has got to be affected by that. And, you know, she actively tried to change herself so that she is “fuckable,” or whatever that means, so she can become the leading lady.

There are so many surprises in the documentary. What surprised you most during the course of making this?

The details we found out about Simon were mind-blowing, and somehow managed to get worse. What you see onscreen is just the tip of the iceberg of what we were hearing—the people, women and men, that he bamboozled and the people who were still afraid to speak out for some reason. I guess they have shame about it. The folks that he conned along the way, the people who were traumatized by him…I was not expecting to see this kind of carnage he left behind.

On a lighter note, what I think surprised me is the consistency of the way people talk about Brittany—people who knew her as a child, who worked with her, even at the very end. The love and admiration they had for her…their descriptions of her generosity. That did not change about her. She still was the same person who moved to L.A. with these bright, bright eyes and all this hope. Bad things happened to her, and the end of her life is very tragic and sad. But from talking to these people, even at the end, I do think she was still that same person.

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