"Making a Murderer" would've likely had to shut down production if the Wisconsin government had its way.

The filmmakers referenced the threat to the series during a Twitter Q&A on Wednesday when answering a question about the challenges of making the Netflix docuseries.

—Making A Murderer (@MakingAMurderer) January 20, 2016

—Making A Murderer (@MakingAMurderer) January 20, 2016

—Making A Murderer (@MakingAMurderer) January 20, 2016

—Making A Murderer (@MakingAMurderer) January 20, 2016

“The state wanted any statement Steven made … and statements by others who might have knowledge or claim to have knowledge about who was responsible for the death of Teresa Halbach,” director Laura Ricciardi said in a previous interview with Buzzfeed.

The subpoena was issued in the fall of 2006, about a year after Ricciardi and co-director Moira Demos relocated from New York City to Manitowoc County, Wisconsin, to document the trial of Steven Avery. Avery was being tried for the murder of Teresa Halbach, a photographer last seen alive on the Avery property.

In order to fight the subpoena, they had to prove that their footage wasn't unique.

Directors Laura Ricciardi (left) and Moira Demos (right) with cinematographer Iris Ng (center) on the set of the Netflix original documentary series "Making a Murderer." Netflix “Our argument in trying to get the court to throw out the subpoena is that the state has access to all of this material. Steven is currently incarcerated. All of his calls, all of his visits are being recorded, so they don’t need to get that from us," Ricciardi said.

The women had made inroads in the community at the time. They had become totally accepted by Avery's friends, family, and supporters at his request. They also made connections with local media and were allowed to be part of the media pool during the trial. The filmmakers feel the state's subpoena was "a fishing expedition."

"We really think it was an effort by the state to shut down our production," Ricciardi said. "There was a way in which, on the one hand, Wisconsin is a very media-friendly state. It was great for us that cameras were allowed in the courtroom. It was great for us that they had a very expansive public-records law, so we could get the types of materials [we did]. On the other hand, the people on the ground, the people in power, weren’t always happy we were there.”

After beating the subpoena, the women worked on the series for several more years. The 10-episode Netflix series debuted in December and became the subject of passionate debates among viewers and the media.