Talk about a surprise ending! By capturing murder suspect Robert Durst’s surprise confession on tape — “What the hell did I do? Killed them all, of course!” — HBO’s “The Jinx” filmmakers Andrew Jarecki and Marc Smerling not only busted open a cold case of the 1982 disappearance of Durst’s wife, Kathie, but also riveted millions of viewers with their painstaking research that uncovered new evidence pointing to Durst’s complicity in the 2000 death of writer Susan Berman and the 2001 murder of his neighbor Morris Black.

Variety: What drew you into producing documentaries?

Andrew Jarecki: We met when we were 9 years old, and we’ve been friends ever since. And when we first had this idea that later became “Capturing the Friedmans,” we decided to work on it together. And that was a fateful thing for us because we have very complementary skills.

Marc Smerling: Documentaries are awesome, because you get to do it with a very tight team, over a period of time and there’s not a huge expenditure. That kept us together as partners. We love the research and the chase and the discovery. We just keep digging and digging. It’s not surprising that we do crime shows in some ways. That passion to find the truth, to find what’s under every rock, is what keeps us together.

Jarecki: We are probably victim-oriented in a way. We realize that the system is very imperfect, and so whether it’s the system indicting somebody for a crime that they didn’t commit in the case of somebody like Jesse Friedman, or somebody who’s not indicted for a series of crimes they did commit, like Robert Durst, there are victims in these stories. That’s our emotional connection very often in this story because we met the family of the missing girl, and because they had been so torn by what had happened to them. We felt that we were doing something other than just portraying a story. We felt that we were getting to a truth that might mean something to them over time. And then when we were watching the final episode and we had Kathie’s family with us, it was so emotional for them. For the first time they got to see the person who killed their dearest relative admit it. And be caught. And that’s something that you don’t get in a narrative feature. You never get that.

Variety: Could you imagine when you started this project that it would become such a topic of conversation?

Jarecki: I think we knew that there was a deep well in this story. And we knew that when Bob Durst first called, he had a story to tell. And we knew that was going to be an interesting story. It was a story that had been very much in the media, periodically, over many years, so when he called and said “I would like to tell my story,” it was obvious to us that there was an opportunity to tap into something really significant.

Smerling: But we didn’t really know what we were getting into. We’d just come off “All Good Things” (a fictional telling of the Kathie Durst disappearance), so we didn’t know if we really wanted to get back into Robert Durst storytelling. But ultimately the interview was such a revelation and it was so in-depth that we had to go there. We just kept going with it and going with it and then we started doing our own investigation and the rest is history.

Variety: What do you look for in a project?

Jarecki: We try to figure out what interests us. We don’t usually go out and say we need a project just because things find you if you are open to them, and we try to be open.

Smerling: We start shooting stuff and then it makes its own project in some ways. But I think we also look for things. I think we’re attracted to stories about families in some crisis.

Jarecki: Some people say that we have maybe a dark sensibility, but I think we just have a deep sensibility, where we feel something very strongly. And in this particular case there was this missing girl, and this family that had lost her. When we first started interviewing members of her family it was really clear how much loss there was, and how much emotion there was. So that was a place to take it.

Variety: You’ve done narrative features, documentary features and now a docuseries. What do you like about working in the medium of television?

Smerling: It’s the greatest because you can stretch the stories out so far. My experience with features is you’re always trying to pack the story into a small box. Whereas television you could just let it overflow the box, it can just open up all the way. And that’s certainly the experience we had on this project. We started it as a feature film and it just got bigger and bigger.

Jarecki: I can’t imagine now how this could have existed as a feature. It just wasn’t right for it.

Variety: Do you think you’ll continue working in television?

Smerling: For sure. Television feels like it’s the future. The whole instigation for making this into a TV series is we were watching all these great series on television like “House of Cards” and “Homeland,” and we were like, what if we tried that with this story? What if we just stretched this story out? So it just seems like an opportunity for storytellers.

Jarecki: A big part of it for us was that because we didn’t go into it thinking we need to make a certain number of episodes. We just went in saying we’ve got so much story, let’s figure out what’s the shortest possible version of this that still tells the story in the rich way that it needs to be told. And so we let the story dictate the length of it, which I think was really lucky that that it worked out the way that it did.

Variety: Why do you think television is enjoying such a renaissance right now?

Jarecki: It’s funny people say television’s the past and now television’s suddenly the future. We’re living it, we’re watching things happen in real time on television, and I think for us, having made this it’s so much more a part of the national conversation than if we had made it as a film. No matter how many people see a film in a theater, which is a wonderful way to see a film, it doesn’t have the currency. It almost can’t have the currency as when millions and millions of people have access to it instantly.

Smerling: Television is changing in a really interesting way, whereas the three-act structure of movies or four-act structure of movies has been the standard for the last 100 years. Now television is offering another sort of structure that stretches that structure out and people are really responding, whereas television used to be one episode, one crime, one story. Now they’re all soap operas to a large extent. That’s not a dirty word in television, but it’s true that all these stories are being stretched out and that allows a lot of creative in-between areas where you can really explore characters, you explore little avenues and it’s a lot more fun. People love to binge watch television. Now, you see it when you want to see it, and you stick with it as long as you want to stick with it.

Variety: What’s next for you? Do you have another project lined up?

Smerling: Everybody’s talking about another “Jinx,” which is hard to match. I don’t know how we do that. You can’t just conjure these stories out of pure air. They kind of come to you. So I think we’re waiting for something to come to us that would be exciting. I do think we’ve caught the television bug. It’s a great format for us.

Jarecki: Because the commitment to watching a television show is actually much less than the commitment to watching a feature film, it means that people can graze and try things. And if you make stories that are compelling, they’ll stop and they’ll engage, and they’ll watch it. You have to be very sure that you want to go see a feature film. In television you’re welcome to try things. And I think that’s part of the experimental nature of of making anything, is that the audience also has to be willing to and able to experiment. You have to let the audience try your thing and in television they really do, they can. They have so many thousands of choices, it’s an opportunity for them to say I don’t know if I’m going to like this or not, but I’m certainly going to try it for two minutes. And our job is to make them stay, which happily they sometimes do.