Almost a month to the day that their 10-hour documentary Making a Murderer quietly debuted on Netflix, and subsequently became the most-buzzed series of the holiday season, co-directors Laura Ricciardi and Moira Demos defended the controversial series, and discussed plans to continue telling Steven Avery's story.

"We've had several telephone conversations with Steven Avery," said Ricciardi. "We did record those calls, with an eye towards including them in any episodes, should there be any future episodes," she said during a panel discussion at the Television Critics Association winter press tour.

Avery is serving a life sentence for the 2005 murder of Teresa Halbach, which occured two years after he was released from prison after serving 18 years for a crime he didn't commit. As new witnesses and information come to light as a result of the media attention generated by the series, Demos and Ricciardi said they "are ready to follow leads if there are significant developments. We will be there." (Earlier today, when asked about the potential for a followup episode or second season, Netflix chief content officer Ted Sarandos said, "the story is still unfolding, so we'll certainly take a look at it.")

The directing duo defended their work from accusations they intentionally overlooked damning evidence against Avery and did not include interviews with the prosecution. The series has drawn the ire of Nancy Grace, who is convinced of Avery's guilt.

Ricciardi said she approached the story as a filmmaker, not a lawyer. "We did not set out to convict or exonerate anyone, we set out to examine the criminal justice system and how it's functioning today," she said. "We were not putting on a trial but a film."

"It just would have been impossible for us to include every piece of evidence that was submitted to the court," said Ricciardi, explaining that she and Demos focused on the evidence the prosecution thought was the most compelling. "Of what was omitted, was that really significant? The answer is no."

With the recent media backlash, "it's now on a national scale that the media are demonizing this man in order to prove his guilt," said Ricciardi. "We showed Steven Avery, warts and all," using multiple sources and fact-checking.

Demos said of the news reports that have attacked the series, "I would challenge people to do some research about what is being presented as truth, and see whether the documentary or the news report has more veracity."

The filmmakers "don't have a stake in his innocence or guilt," said Demos. "If you watch this series, I think it's clear that the American crime justice system has some serious problems, and it's urgent that we address them." She called Making a Murderer "an American story" that extends far beyond this one community. "It's writ large across our country."

Ricciardi said the filmmakers had hoped for "universal access" from all parties involved in the case. "What we got was less than that." And while prosecutors declined "multiple" requests for on-camera interviews, Ricciardi said she and Demos used original footage of them from through the case to represent their point of view.

One notable person involved in the case hasn't yet seen Making a Murderer: Avery himself. "Steven does not have access to this series," said Ricciardi, explaining that the warden denied his request to see the documentary. Instead, "his focus is on the case."

Lisa Nishimura, Netflix's vp of original documentary programming, told Adweek that Making a Murderer's Dec. 18 release date—which initially seemed to indicate that Netflix was essentially burying the show over the holiday season–was in fact chosen with great care.

"As we were producing the episodes, it became very clear that they demand your attention, they're very dense. It's not something you put on and then cook your dinner and watch out of the side of your eye. You really need to engage," Nishimura said. "And as you watch it, it really inspires in one a desire to talk about it, to commune with other people about it. To bounce theories and ideas and just try to process. And we know that the holiday season is one that allows more freedom of time."

Other factors in favor of the holiday season: people want to test out the new devices they receive as gifts, said Nishimura. "And it's also a time where people are engaging socially in a way that they otherwise aren't."