The golden age of the true crime documentary began in earnest on December 18, 2015 when Netflix quietly released a 10-episode series about an obscure murder trial in deepest Wisconsin. From such inauspicious origins sprang one of the TV sensations of the age, as Making A Murderer became the subject of fervent water cooler conversation, even among people who lacked water coolers and rarely had conversations.

Now the story of Teresa Haibach, Steven Avery and Brendan Dassey is to have another chapter, with the smash doc returning for a massively anticipated second season, again helmed by filmmakers Laura Ricciardi and Moira Demos. To fans, the prospect of more Making A Murderer is obviously hugely exciting. For everyone else, it’s the meta overtones that add the spice. What happens when filmmakers revisit a story they themselves had an impact on? What a hall of mirrors we are about to step into.

Series one was seen as casting doubt on the guilt of Steven Avery, jailed for the 2005 killing of Haibach, and of his nephew Dassey’s complicity in the crime. Such was the outcry that their cases were revisited and put forward for appeal. So in a certain sense Making A Murderer part two is about how Making A Murderer applied question-marks to a double-conviction up until then regarded as watertight.

“Building on part one, which documented the experience of the accused, in part two, we have chronicled the experience of the convicted and imprisoned, two men each serving life sentences for crimes they maintain they did not commit.” explained Ricciardi and Demos as they confirmed another run of 10 episodes.

Season one of Making A Murderer tracked the 2007 trial of Avery for the first degree murder of Haibach, a photographer who vanished two years previously after setting off to meet the accused (she was to take pictures of his sister’s minivan, which Avery was putting up for sale). As part of the criminal investigation, Avery’s then 16 year-old nephew, Brendan Dassey, was arrested and convicted as an accomplice to murder, mutilation of a corpse and second degree sexual assault.

The crux of the defence’s case was the police interrogation of Dassey, which took place without the supervision of his parents. Dassey’s’ IQ meant he verged on suffering cognitive disability. Yet a confession he offered was crucial in the case against both him and Avery. His lawyers insisted it was obtained coercively, pointing out that it was almost immediately recanted.

Two years ago, it seemed that Making A Murderer had indeed turned the original trial on its head. A US federal judge ruled Dassey’s confession was unlawfully obtained and his release was ordered.

But in the American justice system the wheels turn slowly, if at all. So it would prove here. Massey remains behind bars owing to an appeal from the Wisconsin Justice Department – which prevented his release pending a further hearing. Just last December, the US Court of Appeals for the Seventh Circuit reversed the earlier appeal and upheld the original guilty verdict.

The case has not rested there. Dassey’s team are preparing for one final effort via an appeal to the American Supreme Court. Only time will tell whether they succeed.

Making A Murderer prompted a renewed push to have Avery acquitted too. In 2017 his team sought a new trial, producing findings which, they claimed, showed his conviction was based on planted evidence and false testimony. However, the motion for a retrial was rejected.

With so much drama to catch up on it seems certain that season two will be as riveting as the earlier series. One difference, though, will be that the defence lawyers who became far-fetched cult figures may not feature. Dean Strang and Jerry Butin emerged as meme-friendly heroes, with the former receiving particular attention in Ireland, due to the appearance in his office of a hurling memento presented by an Irish-American friend. He even popped up on, of all places, the Ray D’Arcy Show on RTÉ One and had sell-out speaking engagements in Dublin and Galway. The bad news for fans of the duo is that they are unlikely to feature as Making A Murderer returns. Instead, Avery has entrusted his fortunes to wrongful conviction attorney Kathleen Zellner. Expect her to become as prominent a figure in series two as Strang and Butin in 2015.

“There were definitely some threshold questions for us,” Ricciardi told Indiewire in 2016, when Netflix green-lit the new season. “The main one being, ‘Is there something to add to this conversation?’ Kathleen, for instance, was someone who has come along and planned to reinvestigate the case and is looking for answers. She’s someone with an incredible track record. We thought, ‘She’s sure to make things happen.’ If that is going to happen, then we want to be part of it.”

Making A Murderer Part Two comes to Netflix on October 19.