(CNN)The conviction of Brendan Dassey, a Wisconsin man who appeared in the documentary "Making a Murderer," has been overturned by a federal judge in Milwaukee, according to court documents obtained by CNN.Dassey was convicted in 2007 in the murder of photographer Teresa Halbach. In overturning the conviction, the judge cited the manner in which a confession was obtained from Dassey, who according to court documents has a low IQ.
Prosecutors have 90 days to bring Dassey, now 26, to trial again or he will be released.
His uncle, Steven Avery, the subject of "Making a Murderer," is in a Wisconsin prison also serving time for Halbach's murder.
The 10-part Netflix series, which was released last December, renewed interest in Avery's ongoing legal troubles, leading to calls for his release and a petition seeking a presidential pardon.
Many of the elements of the case bothered observers.
For example, Dassey -- described in the judge's ruling as having an IQ "assessed as being in the low average to borderline range" -- was questioned without his mother present and appeared to be eager to tell sheriff's officers what they wanted to hear.
And some viewers said that after watching the documentary they believed that the sheriff's office planted evidence to frame Avery for the crime.
Avery was convicted in 1985 in the rape of jogger Penny Beerntsen on a beach near her home in Manitowoc, Wisconsin. After serving 18 years in prison he was exonerated based on DNA evidence connecting the attack to another man.
Avery was released in 2003 and filed a lawsuit against Manitowoc County for wrongful conviction and imprisonment. Two years later, while the suit was still pending, he was arrested in the death of Halbach, whose charred remains were found on his family's auto salvage yard.
Prosecutors laid out their case: Halbach's Toyota RAV4 (which had blood in it, including Avery's) was found on the Avery family's lot. Tissue and bone fragments that matched Halbach's DNA profile were found outside Avery's mobile home.
Dassey, then 16, confessed to authorities that he had assisted his uncle in raping and killing Halbach. He later recanted.
Federal judge William E. Duffin overturned Dassey's conviction based on the way the confession was attained, calling it "so clearly involuntary in a constitutional sense that the court of appeals' decision to the contrary was an unreasonable application of clearly established federal law."
The judge said he didn't believe investigators tried to trick Dassey into confessing but instead misunderstood the constitutional ramifications of telling him that they already knew everything that happened and he would be OK if he told the truth.
"Dassey's confession was, as a practical matter, the entirety of the case against him," the judge wrote.
CNN reached out to former Calumet County District Attorney Ken Kratz, who prosecuted both cases, but didn't get an immediate response.
Kratz has criticized filmmakers Laura Ricciardi and Moira Demos saying they left out crucial evidence that pointed to Avery's guilt -- an accusation the pair has denied.
Netflix said last month it has started production on new episodes of its docuseries that will act as a follow up to Season 1.
The new season, the company said, will revisit the case and be "an in-depth look at the high-stakes post-conviction process" and explore the "emotional toll" on all involved.
CNN's Tony Marco, Lisa Respers France and Emanuella Grinberg contributed to this report.
