Making a Murderer: Part 2 is available on Netflix

questions. “You don’t guess with something like this, Brendan,” she told him. “Well, that’s what I do with my homework,” he replied.

His appointed defence lawyer, Len Kachinsky, was dismissed by a judge for failing to protect his interests. After his conviction in 2007, Dassey’s case was taken over by Steven Drizin, from the non-profit Center on Wrongful Convictions of Youth, in Chicago.

He handed the videotaped confession to third-year law student Laura Nirider.

“I saw a 16-year-old, intellectually disabled child trying to confess to a crime that he couldn’t even describe, in the hope that he would be sent back to school. I was heartbroken and outraged and it changed the course of my career,” Nirider says. She now represents Dassey alongside Drizin and believes that Kachinsky was trying to implicate his own client.

The first video interview showed detectives attempting to get Dassey to provide a detail that was not in the public domain — that Halbach had been shot twice in the head. They asked him what happened to her head, to which Dassey’s attempted answer was that Avery had cut off her hair. Pressed again, he said that Avery had punched her, then, finally, as the detectives lost patience and asked, “Who shot her in the head?”, Dassey answered, “He did.”

Kratz called a press conference and proceeded to present the unverified details of the confession as facts. This is the moment at which, Drizin says, the prosecutor “destroyed the presumption of innocence of Steven and Brendan”.

“I’ve seen cases where police and prosecutors leak information to the public about their case, but to have a prime-time press conference on TV and radio in the market where the case is going to be tried, that is replayed over and over again . . . I’ve never seen anything that egregious in 35 years as a lawyer,” says Drizin.

The series landed with a bang, polarising opinion about Avery’s guilt. Despite the evidence against him — including burnt bone fragments recovered from a fire pit close to his trailer — some viewers were so incensed by what they saw as a miscarriage of justice that more than half a million signed a petition to Barack Obama, then President, asking that Avery receive a pardon.

Others criticised the series for being partial. The New Yorker published a piece — “Dead Certainty: How Making a Murderer Goes Wrong” — claiming that the filmmakers had erred in displaying “unwarranted certitude” about the innocence of their subjects. The article, like many others, repeated the claim that DNA from Steven Avery’s sweat — “nearly impossible to plant” — had been found on the latch under the bonnet of Halbach’s vehicle. In episode two of the new series, Kathleen Zellner, who took on Avery’s case after watching the Netflix series, re-evaluates this damning piece of evidence, with startling results.

“She makes discoveries that really change your understanding of why it is Steven and Brendan got convicted, and also what it is that may have happened to Teresa,” says Ricciardi. “She approaches it very scientifically,” adds Demos. “She starts with a hypothesis, designs an experiment, and there are times in the series where you see her make a discovery and change her mind.”

The prospect of a long struggle to overturn the convictions meant that a second series had not been certain.

“It was not anticipated or planned,” Ricciardi says. But Zellner’s entrance gave the fight to overturn Avery’s conviction a fresh impetus, while Drizin and Nirider continued to campaign on behalf of Dassey.

How do the film-makers respond to the accusation that they too readily bought into Avery’s story in the first series, covering up or wilfully ignoring certain facts? “Anybody who says that missed the point of the series, and they also don’t understand our process,” Demos says. “Many of the people stating those claims have a motive and an agenda, whereas we didn’t. We were trying to make the defence case as strong as it could [be] and the prosecution case as strong as it could [be].”

In their gut, what do they think happened to Halbach?

“We don’t know,” says Ricciardi. “It’s our job not to judge. It’s our job to show it, accurately. Of course, we have opinions about things that we witnessed or documented but they’re irrelevant to our work.”

But they do have private opinions?

“Not about actual innocence we don’t, because we don’t presume to know what happened to Teresa Halbach,” says Ricciardi. “It’s the job of the investigators to determine that.”

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