Serial, which ran its sixth episode this week, has made as big a splash as is possible for a new podcast (from experienced pros). It was created by Koenig — a This American Life vet — with Ira Glass as the editorial adviser, and approaches its topic with the same friendly earnestness as the public radio giant, feeling, at least at first, like a lazy Sunday morning coffee-and-newspaper kind of listen. But there's a high-wire tension to it that TAL doesn't try for, even at its most in-depth and reported, and that's thanks to Serial's very nature.

Serial is ongoing, and episodes are still being completed, and if there's some sense of where it might be headed, there's a riveting lack of certainty. It's a show that has the capacity to break out past the devoted but limited typical podcast audience. It's a better, if more terrifyingly precarious, mystery than anything on television at the moment, and it's all real, a juicier-than-fiction true crime saga on par with Jean-Xavier de Lestrade's mini-series The Staircase.

It was easy to assume, listening to that initial episode, that Serial's aims were to exonerate Syed. That's why Rabia Chaudry, a friend of Syed's, brought the case to Koenig in the first place, and as Koenig pointed out, "as for physical evidence, there was none — nothing." Syed was convicted mainly on the testimony of one of his casual friends, a guy named Jay who said he helped Syed dispose of Lee's body. It's a setup that seems like it could lead to all sorts of discoveries of injustice.

But as Koenig delves into the nearly decade-and-a-half-old story, the truth becomes more fascinating and less and less simple, until you feel like you should set up a wall of photos and evidence, like an obsessive detective in a movie. Episode 2 looks at Lee's relationship with Syed, a romance between the very American, K-Ci & JoJo-listening, pager-sporting '90s teenage children of first-generation immigrants that — depending on who you believe — either ended amicably or bitterly. Then the show goes on to discover some serendipitous weirdness regarding the person who found Lee's body in Leakin Park, to examine the enigmatic Jay, who describes himself as the perceived "criminal element" alongside these overachieving high school kids, and to trace the route that Syed and Jay took on the day of the murder.

In the latest episode, by my estimation the strongest and most uneasy installment yet, Koenig lays out the many uncertainties and doubts about innocence maintained by Syed, who has been a determinedly affable presence on the phone from prison through the show, a 33-year-old who calls Koenig "man" and peppers his speech with "you know what I'm saying?" Serial touches on all the things that he can't explain, like a key phone call from his cell, or his behavior when Lee was first reported missing. Maybe he's lying. Maybe he's a sociopath. Maybe he isn't, and a kid he used to smoke pot with but only described as a casual acquaintance has made him a very unfortunate scapegoat. Maybe the culprit was someone else entirely. Maybe it's something more complicated.

Syed has a tough question for Koenig as well, as she clearly hasn't come into his life to be an unquestioning champion. He asks her why she's so interested in his case — a question that could be posed to all the listeners who are eagerly piping his story into their own lives via their headphones each week. Koenig explains that it's because of the details of the case, which do encompass some rich themes of class and race and family, but mostly it's because of him, because he's so intriguing, a "nice guy" who's gone to jail for doing such a terrible thing. And after a long pause, he replies, "You don't even really know me, though, Koenig."