Serial: Podcast sensation returns for a second series investigating capture of US soldier in Afghanistan

The first series of Serial generated such a response that it led to an appeal being granted to convicted killer Adnan Syed

Sergeant Bowe Bergdahl was released by the Taliban last year in an exchange with five prisoners from Guantanamo Bay (Sergeant Bowe Bergdahl)

The podcast sensation Serial is to return for a second series and investigate the mysterious disappearance in Afghanistan of an American soldier who was then held captive by the Taliban for five years.

Because Sergeant Bowe Bergdahl was charged with desertion and appeared at a court martial preliminary hearing only last week, the makers of the podcast have appealed to other sections of the media not to engage in “wild speculation” on the series.

The first series of Serial generated such a response that it led to an appeal being granted to convicted killer Adnan Syed, who had been jailed for the 1999 murder of teenage athlete Hae Min Lee. The 12-episode podcast, which was downloaded 68 million times, was described as “an audio game-changer” and has been part of a revival of real life crime media.

'Serial' podcast presenter/reporter Sarah Koenig (Getty) (Getty Images)

Broadcast on National Public Radio in America, Serial topped the iTunes podcast chart for three months. Sarah Koening, the host and producer, spent over a year researching the Hae Min Lee case and described events in minute detail, encouraging listeners to play at being amateur sleuths. Within three weeks of the finale, Syed, who was convicted in 2000, was given leave to appeal.

Sergeant Bergdahl’s case is more current. He was released by the Taliban last year in an exchange with five prisoners from Guantanamo Bay, a deal which attracted criticism that it breaches American policy of not negotiating with terrorists. The circumstances under which he originally left his post in Afghanistan while on counter-insurgency duties remain unclear. A Pentagon investigation in 2010 concluded that he had walked away from his unit. But the soldier’s lawyers have suggested that he had a history of mental health problems and that, although he left his post, his intention was not to abandon the army.