Recently, a federal judgeoverturnedDassey's life conviction, persuaded by the argument that police officers coerced his confession.
On Friday, the full Seventh Circuit Court of Appeals ruled 4-3 that Dassey's confession should stand, though one dissenting judge called the ruling "a profound miscarriage of justice".
In 2005, Dassey, then 16, confessed that he had helped his uncle, Steven Avery, rape and kill the woman.
The issue was whether the state court findings upholding the confession constituted an unreasonable application of Supreme Court precedent or an unreasonable view of the facts, according to the majority decision by JudgeDavid Hamilton.
Rovner wrote a separate dissent saying courts need to update their understanding about the nature of coercion in confessions.
Chief Judge Diane P Wood added: "Without this involuntary and highly unreliable confession, the case against Dassey was nearly non-existent".
Dassey has remained in prison while the state appeals.
The three dissenting judges wrote that the decision was "a profound miscarriage of justice".
The new evidence comes from Brendan Dassey's brother, Bryan, who told the Wisconsin Department of Justice in November 2005 that a third Dassey brother, Bobby, had told him he saw Halbach leave the property alive on October 31.
In 2007, Dassey was sentenced to life after being convicted of being party to first-degree murder, mutilation of a corpse, and second-degree sexual assault. Dassey's IQ is in the "borderline deficiency" range, and at the time of his arrest he was enrolled in special education classes at high school.
They also said they intend to continue to fight for Dassey, including through petitioning the U.S. Supreme Court to review Friday's ruling. He was interviewed without a supportive adult present. "Indeed, when such tactics are applied to vulnerable populations, the risk of false confession grows intolerably".
Laura Nirider and Steven Drizin, Dassey's lawyers, said in a joint statement to HuffPost that they are "profoundly disappointed" by the four judges' decision.
But, it turns out that's not likely for Brendan Dassey anymore.