A convicted murderer in Wisconsin allegedly confessed to killing Teresa Halbach, the photographer whose 2005 death gained renewed interest with the release of the Netflix docuseries "Making a Murderer."

Halbach was killed Halloween night after visiting the property of Steven Avery, who along with his nephew, Brendan Dassey, was convicted of the murder. Both have said they are innocent.

A second docuseries on the case, "Convicting a Murderer," is currently in the works by director Shawn Rech.

Teresa Halbach Halbach Family via Herald Times Reporter/AP

During a recent interview with Newsweek, Rech said as his crew was filming the series, they were given the alleged confession by a "notable convicted murderer from Wisconsin." Rech did not name the inmate and did not disclose what the confession said, but said the confession did not come from Avery or Dassey.

Rech did not return a request for comment.

"We haven't confirmed the legitimacy of the confession, but seeing as it was given by a notable convicted murderer from Wisconsin, we feel responsible to deliver any and all possible evidence to law enforcement and legal teams," he said.

"Having been in production for 20 months, we've uncovered an unfathomable amount of information and evidence that is leading us to the truth. Our investigation does not end here," he continued.

The Manitowoc County Sheriff's Office did not immediately return NBC News' request for comment.

Avery's lawyer, Kathleen Zellner, said in a tweet Monday that her office has received the handwritten confession but "it is worthless unless it is corroborated." Laura Nirider, an attorney for Dassey, tweeted that they are aware of the alleged confession and did not offer any further comment on it.

Brendan Dassey is escorted into court for his sentencing in Manitowoc, Wisconsin, in 2007. Eric Young / The Times Reporter via AP

Both Avery and Dassey were given life sentences in 2007 for Halbach's murder. Dassey was 16 when he told investigators that he helped his uncle rape and murder the photographer and then dispose of her body.

No physical evidence linked Dassey to the crime but he was convicted on his statements to two investigators, which some have argued were improperly obtained. Lower courts found that Dassey's confession, which was done without a lawyer or his mother present, was involuntary, but in June 2018 the 7th U.S. Circuit Court of Appeals in Chicago upheld the conviction. Avery is continuing the appeal process.

Both have said that they were framed for the murder by officers who were angry with Avery for suing the county over his wrongful conviction for a sexual assault. Avery spent 18 years in prison for that case before DNA proved he did not commit the assault.