The young prisoner featured in Netflix’s controversial documentary “Making a Murderer” was coerced into confessing to a 2005 killing, and his conviction should be overturned, according to a federal appeals court decision that could set up the case to go to the Supreme Court.

The detectives who interrogated Brendan Dassey manipulated the then-16-year-old, fed him facts that investigators wanted to hear, acted like father figures and made false promises of leniency — all to extract a confession that fit their theory, according to a lengthy opinion issued Thursday by a three-judge panel of the U.S. Court of Appeals for the 7th Circuit. The 2-to-1 decision upholds a federal judge’s ruling last August.

“No reasonable court could have come to the conclusion that Dassey’s confession was voluntary,” according to the opinion, which includes a dissent statement warning that the decision could hamper investigations.

Dassey, now 27, is serving a life sentence for the death of 25-year-old Teresa Halbach, who disappeared on Halloween in 2005 after she went to take photos for an auto magazine at a salvage yard owned by Dassey’s uncle, Steven Avery, in Manitowoc County, Wis. Avery was tried separately and is serving a life sentence without the possibility of parole.

The Center on Wrongful Convictions at Northwestern University, which is representing Dassey, says the ruling places him “a significant step closer to achieving that justice.” Dassey has been in prison for more than a decade.

“We are overjoyed for Brendan and his family, and we look forward to working to secure his release from prison as soon as possible,” the center said in a statement.

Johnny Koremenos, spokesman for the Wisconsin Department of Justice, called the decision “erroneous” and said the agency plans to request the entire 7th Circuit or the Supreme Court to review the ruling.

“We continue to send our condolences to the Halbach family as they have to suffer through another attempt by Mr. Dassey to re-litigate his guilty verdict and sentence,” Koremenos said in a statement.

The death of Halbach and the conviction of Avery and Dassey placed Manitowoc County in the national spotlight. In December 2015, Netflix released a 10-part documentary series exploring the life and conviction of Avery. The series was filmed over a course of 10 years.

Last August, a federal judge in Wisconsin ruled that Dassey’s confession was illegally obtained and that he should be released unless the state decides to retry him.

Detectives interviewed Dassey multiple times in the months after Halbach’s disappearance. During a three-hour interview in March 2006, Dassey confessed that he raped Halbach, cut her throat, tied her up and took her to Avery’s garage, where Avery shot the young woman in the head. The two then burned her body, Dassey told detectives.

Dassey offered conflicting versions of his story, according to the appeals court opinion. He initially said that he only helped Avery clean some fluid from the garage floor. His story evolved to one that incriminates him in disposing of Halbach’s body. In another version, Dassey told detectives that he heard screaming from his uncle’s house as he brought him his mail. He went inside and found Halbach, naked and handcuffed to Avery’s bed. Later, Dassey confessed to raping and killing Halbach.

But Dassey’s confession, according to the ruling, was “a story crafted by the investigators” and not by him. The appellate judges pointed to signs of fact-feeding and Dassey’s desire to please his interrogators by agreeing with them or telling them what they wanted to hear.

Throughout the interrogation, investigators told Dassey, then a high school sophomore whose IQ had been measured between 74 and 81, that “honesty” is what they wanted to hear and that it’s “the only thing that will set you free.”

But “it became clear that ‘honesty’ meant those things that the investigators wanted Dassey to say,” the ruling states.

The judges added: “Whenever Dassey reported a fact that did not fit with the investigators’ theory, he was chastised and told that he would not be ‘okay’ unless he told the truth. And this pattern continued until Dassey finally voiced what the investigators wanted him to say, seemingly guessing, or the investigators fed him the information they wanted.”

Detectives also gave Dassey fatherly assurances, the opinion states.

During one of the interviews, for example, Wisconsin Department of Justice Special Agent Tom Fassbender said: “Mark and I, yeah, we’re cops, we’re investigators and stuff like that, but I’m not right now. I’m a father that has a kid your age too. There’s nothing I’d like more than to come over and give you a hug cuz I know you’re hurtin’. Talk about it … I promise I will not leave you high and dry.”

The other detective, Mark Wiegert of the Calumet County Sheriff’s Department, touched Dassey’s knee to assure him, the opinion states.

In his 24-page dissent, Judge David Hamilton said the majority’s decision would burden police and prosecutors’ ability to investigate crimes.

“It calls into question standard interrogation techniques that courts have routinely found permissible, even in cases involving juveniles,” Hamilton wrote.

The judge also said that Dassey was not mistreated or threatened, and that his mother consented for him to be interviewed without her.

“If such gentle interrogation can be treated as unconstitutionally coercive, what should police do next time an investigation leads to a teenager with some intellectual challenges?” Hamilton wrote. “Few wrongdoers are eager to own up to crimes as serious as Dassey’s … Today’s decision will make some police investigations considerably difficult, with little gained in terms of justice.”

Avery is seeking a new trial.