Ellen Horne had a problem yesterday morning: she couldn’t find the TV remote control to occupy her eighteen-month-old daughter. “I imagine she’ll just play by herself,” she laughed.

DetourRadiolabSXSW300This was the least demanding task she’d had to perform in three months. Starting in January, Horne, the executive producer of WNYC’s immersive science radio program Radiolab, had overseen a project unusual even by Radiolab’s standards: guiding smartphone users through a walking tour of Austin, Texas, tracing the path of the “Servant Girl Annihilator,” a mysterious serial killer who stalked the city’s streets in 1885. Radiolab, in conjunction with the mobile app startup Detour, had just finished rolling out the experience before the more than 50,000 people who annually attend the South by Southwest Interactive Festival. Playing with her baby girl was a long way from helping the world’s most important tech and media professionals feel what it was like to walk the same streets as a murderer.

The project was among the most excitable features presented at South by Southwest. Media producers from around the country walked through the streets around the conference, listening to an interactive program about one of Austin’s darkest moments. It was also a sales pitch by Detour, the company that developed the app and suggested that this could be a new way for media companies to not just tell an entertaining yarn from ancient history, but package contemporary, local issues in a physical, walked experience.

If it works, media consumers could understand emerging stories in a way they never could before. They could walk around a proposed housing project or oil refinery, for example, stopping at a street corner and pulling up images of what the project might look like, environmental records of the developer, or audio recordings of the history behind the site. But how much time and expense would such projects take, and can media companies really afford to create this new kind of storytelling? When Ellen Horne set out to discover the story of the Servant Girl Annihilator, she also discovered just how complicated such new storytelling could be.

The project started last August, when Andrew Mason, the co-founder of Groupon and founder of Detour, got in touch with Radiolab host Jad Abumrad and suggested that the two do something together. Detour, which offers “location-aware audio tours” that use GPS technology to give listeners a chance to wander a neighborhood and understand its history and culture, sounded interesting. But, Horne said, Abumrad was “too busy to pee.”

That all changed one month later, when Abumrad and Horne flew into San Francisco on a business trip and sampled some of Detour’s walking tours. They walked through Fisherman’s Wharf, the hard-luck Tenderloin neighborhood, and the Beat Generation’s stalking grounds. “We immediately saw the opportunity of working in this new medium as something that would give us a creative stretch,” Horne said. “And would push out new challenges for us and new opportunities.”

Horne, Abumrad, and Mason sat down and agreed to show the world’s media producers what this kind of storytelling could really accomplish. And they decided to do it on one of the world’s biggest stages. But it turned out that this sort of project takes time, money, and staff – maybe more resources than most media outlets are willing to commit.

After finding the story they wanted to tell, Radiolab’s producers flew one of their staff down to Austin, to walk around the streets where the murders took place, photograph the area, and begin to conceptualize how the story would unfold. Back in New York, the producers storyboarded the tour itself, to figure out the order in which walkers would travel. Meanwhile, local musicians were found to offer sounds that could provide an aural atmosphere of Austin in 1885 – it helped that so many musicians knew and loved Radiolab. Eventually, they realized they couldn’t put it all together without being on the ground in Austin for an extended length of time. “I think it surprised us … that so much of the work had to be physically on site,” Horne said.

And there were other, unexpected challenges. Radiolab’s producers had to know which streets would be closed off to accommodate the South by Southwest festival, foreclosing the possibility of certain narrative threads. Some blocks were shorter than others, and not everyone walks at the same pace, complicating the question of pacing the audio tour.

Ultimately, five Radiolab staffers spent roughly three months researching the story, mapping out the route, collecting ambient sound and music, and finding locations that, in some instances, smelled like the period they were trying to evoke. And this was for a story that took place more than a century ago, with no one left alive to challenge the reporting or threaten to sue if the show got anything wrong.

The tour Horne and her colleagues pulled together may have been fascinating – because it’s a location-based mobile app, you have to be in Austin to experience it for yourself – but Radiolab is comparatively well funded. For all its bells and whistles, the Radiolab serial killer tour may be too expensive for most media outlets to duplicate, at least by the program's standards. “I’m not sure that the way that we did it would be a transferable model to anyone else,” Horne said.

When the time came for South by Southwest, both Horne and Detour’s Andrew Mason were on hand in Austin, ready to show off their product. Horne and other producers personally lead dozens of tours to attendees. But as remarkable as the experience may have been, Mason was reluctant to show off how many people took the tour. “We’re more focused on the long-term than short-term bumps from events like SXSW,” he texted.

Correction: A previous version of this story misidentified the age of Ellen Horne's daughter.