The appeals court handling "Making a Murderer" subject Brendan Dassey's case today upheld a 10-month-old ruling that the 27-year-old's murder conviction be overturned.

Last August, a federal judge in Milwaukee overturned the 2007 conviction for allegedly murdering Teresa Halbach, saying that Dassey's confession was obtained when investigators gave the then 16-year-old "false promises."

Read: 'Making a Murderer' Brendan Dassey to Remain in Prison Pending Appeal

Related: 'Making a Murderer' Brendan Dassey's Conviction Overturned

The judge, William Duffin, also cited "Dassey’s age, intellectual deficits, and the absence of a supportive adult," in ruling the confession "involuntary."

In 2007, Dassey was convicted as a teenager along with his uncle Steven Avery of murdering Teresa Halbach two years earlier. Dassey was sentenced to life in prison. Then, last year, his story and interrogation were shown as part of the Netflix series, "Making a Murderer," which raised questions about the case.

The state appealed Duffin's ruling late last year and it was taken to federal appeals while Dassey remained in prison.

The original ruling was upheld by a three-judge panel, Dassey's lawyer Laura Nirider confirmed to ABC News.

"What better way to join Twitter than to announce some very good news: Victory in Brendan #Dassey appeal. Thank God. #MakingaMurderer," she tweeted.

Another of Dassey's lawyers, Steven A Drizin, added on social media that "7th Circuit AFFIRMS Judge Duffin in 2-1 decision. This round goes to Brendan Dassey 2-1."

THIS JUST IN. 7th Circuit AFFIRMS Judge Duffin in 2-1 decision. This round goes to Brendan Dassey 2-1 (Judge Hamilton dissenting). — Steven A Drizin (@SDrizin) June 22, 2017

"We are overjoyed for Brendan and his family, and we look forward to working to secure his release from prison as soon as possible. As of today’s date, Brendan Dassey has lost 4,132 days of his life to prison," his legal team wrote in a statement.

The state has 90 days to retry Dassey. A spokesman for Wisconsin Attorney General Brad Schimel told ABC News that they are "evaluating" the decision.

"We anticipate seeking review by the entire 7th Circuit or the United States Supreme Court and hope that today’s erroneous decision will be reversed," the spokesman said. "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."