'Free Adnan" T-shirts are now for sale in support of a Maryland man serving life for killing his former high school girlfriend, reminiscent of the merchandising that once surrounded another convicted killer, Mumia Abu-Jamal.

Here's another commonality: NPR once commissioned Abu-Jamal for audio commentaries (which were canceled before they aired), and Serial is a spinoff of This American Life, which airs on more than 500 public radio stations across the country. Adnan Syed's mouthpiece is Sarah Koenig, who offered her interpretation in 12 podcast installments, which CNN reported in December as having been downloaded 40 million times, making Serial the most popular podcast ever.

Syed was convicted in 2000 of murdering 17-year-old Hae Min Lee. Spoiler alert - in the final episode of Serial, Koenig concludes that she "can't swear that he's innocent" but that "most of the time I think he didn't do it."

The combination of a whodunit, Koenig's mellifluous voice, and excellent production values has created a New Age version of an old-time radio play. But with its breezy presentation and cliff-hangers, it is not a trial-like presentation of evidence and lacks the cross-examination necessary for a real search for truth, a point that might be lost on whoever is inclined to buy the merchandise.

Koenig might be 45, but she invokes like and anyway and weed enough times to develop an adolescent street cred while convincing a New Millennial audience that she's a modern-day Nancy Drew, simply trying to figure out whether Syed is guilty. Time and again, however, she tips her hand.

From the first episode, it is clear her interest lies in giving voice to the convicted killer, whom she describes as having "giant brown eyes, like a dairy cow," as she wonders, "Could someone who looks like that really strangle his girlfriend?" (At least in this instance she catches herself and offers: "Idiotic. I know.")

But as the series unfolds, her bias becomes increasingly obvious. In Episode 6, during one of her many calls with Syed (she says there were 40 hours of interviews with him behind bars), she tells him, "You're a really nice guy and I like talking to you."

Even he seems taken aback, telling her she hardly knows him. Not until Episode 8 do listeners learn that, despite his loquaciousness behind bars, Syed did not testify on his own behalf. Of course, he has a Fifth Amendment right, but it's information that should have been shared sooner. Only in Episode 10 do we learn that part of Syed's pending appeal is arguing that his lawyer should have negotiated a plea agreement. And why wait until Episode 11 to share that the now-sympathetic-sounding man doing life once stole from his mosque? Perhaps because people would have stopped listening had the information been given sooner.

Koenig interviews plenty of legal experts in the course of the 12 episodes, but missing is a psychiatrist. It would have been interesting to hear what a professional would say if permitted to listen to all 40 hours of the interviews with Syed. Perhaps that he's a narcissist. That might explain why, in Episode 11, he tells Koenig, "It doesn't matter to me how your story portrays me, guilty or innocent - I just want it to be over." Hmmmm. The podcast is the best gift ever to have fallen into his lap. The attention generated by the entertainment has boosted his shot at an appeal, with a decision probably coming this month.

In the final episode, Koenig asks: "Did we just spend a year applying excessive scrutiny to a perfectly ordinary case?" Yes, is the clear answer, and with a steep societal cost.

There is a well-documented no-snitching problem in urban America, in which too many people refuse to testify against evildoers for fear of their safety. Consider the case of Kaboni Savage, who in 2013 was given 13 death sentences - 12 of them for murders he ordered or had committed, including the deaths of six relatives of an informant - the 13th for witness retaliation. And this month in Washington, the Post reported that at least 37 people had been killed in the District and Maryland - the scene of Syed's crime - since 2004 because they snitched. The Post reported "more than 320 witnesses have been intimidated in Maryland over the past decade in incidents that led to court charges, including non-fatal shootings, assaults, and threats of bodily harm, records show."

At its core, Serial is an indictment of Jay, a classmate of Syed's who confessed to helping bury Lee's body before turning state's evidence against Syed in return for leniency. In virtually every episode, Koenig targets Jay's credibility with circumspection she reserves for only him. An admitted shoplifter elicits a giggle from her in Episode 9, but Koenig accepts the woman's story. Jay doesn't get the same consideration, perhaps because to accept his version is to cut short this series long before Episode 12.

In that final episode, Koenig naively wonders, "Why would a guilty man allow me to do his story?" Really, Sarah? Bob Dylan said it best, "When you ain't got nothing, you got nothing to lose."

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