Serial’s in-depth exploration of a true-crime story made it the most-listened to podcast in the world, but one particularly unfortunate human error nearly destroyed its credibility.

Released in 2014, Serial garnered millions of listeners as it used gripping investigative journalism techniques to revisit the 1999 murder of Maryland high school student Hae Min Lee.

Listeners were obsessed with host Sarah Koenig’s efforts to uncover whether Lee’s then-boyfriend Adnan Syed, who is currently serving a lifetime jail sentence, was in fact wrongfully convicted of the crime, despite a lack of evidence.

The podcast endeavoured to remain impartial and used only witness testimony and court documents to tell its story — efforts nearly completely undone by an accidental social media post in 2015.

Speaking at the Sydney Opera House’s BingeFest festival, Serial co-creator Julie Snyder discussed the problem of remaining impartial and managing the unexpectedly massive online reaction the podcast received.

Snyder said she and Koenig were scrupulous in their management of listeners’ online commentary on Serial’s social media pages, in order to avoid any legal strife.

But one such attempt to moderate inflammatory comments nearly had disastrous ramifications.

A year ago, at the height of the podcast’s popularity, a Serial staffer tasked with filtering Facebook comments attempted to set up a filter for common provocative phrases, one of the most prevalent being “Adnan did it”.

Instead, the staffer accidentally posted that exact phrase to Serial‘s official Facebook page. Worse, he was logged in on the podcast’s official account.

The unfortunate accidental post.

Thus, to those following the page, it appeared Serial had inadvertently declared Syed, its mysterious and widely supported subject, was, in fact, guilty of murder.

The staffer quickly deleted the post, but not before internet sleuths captured it in screenshots and shared it on forums, where its validity was fiercely debated.

Thankfully, according to Snyder, most fans dismissed the post as the result of Photoshop or a hacking, and the furore died down as quickly as it began.

The staffer also managed to keep his job, but Snyder joked he is still “haunted” by his error.

Julie Snyder speaks to the crowd at Bingefest in Sydney. Photo: Prudence Upton

Serial‘s coverage of Syed’s case lead to a hearing earlier this year to examine grounds for a retrial based on the questionable reliability of mobile phone evidence and the failure of Syed’s lawyer to call upon a key alibi witness at the time of the original trial.

In July a judge overturned Syed’s conviction and granted his request for a new trial — a decision that has been met with widespread opposition by state attorneys in Maryland.