The convicted killer featured in Netflix's hit documentary series "Making a Murderer" filed for a new appeal Tuesday for his release.
Avery, who was convicted in the death of photographer Teresa Halbach in 2007, filed the appeal without the assistance of a lawyer, Wisconsin Public Radio reported.
The appeal claims authorities used improper search warrants to illegally obtain evidence.
Avery was wrongfully convicted of trying to rape and kill a woman in 1985. Although DNA evidence would later exonerate him, Avery spent 18 years in prison mired in a legal battle that "Making a Murderer" covers in its first episode.
In 2005, Avery was preparing to sue Manitowoc County for the wrongful conviction when he was arrested in Halbach's murder.
The documentary series has captured national attention for casting doubt on the 2007 murder case against Avery, but has been met with some resistance. Ken Kratz, the main state prosecutor in the case, told Maxim that the series' directors cherrypicked facts that created an incomplete picture of Avery's conviction.
"If you pick and choose and edit clips over a 10-year span, you're going to be able to spoon-feed a movie audience so they conclude what you want them to conclude," he said.
More than 400,000 people signed a recent online petition that urged President Barack Obama to pardon Avery and his nephew. The White House responded, saying the president doesn't have the legal authority to issue pardons in this case because Avery was convicted of state, and not federal, crimes.
Chicago attorney Kathleen Z. Teller said last week that her legal team would assume the "full and and complete representation of Steven Avery," adding that they're prepared to present new evidence.
READ MORE: 'Making a Murderer' interrogates fairness of justice system.