A federal appeals court in Chicago said Wednesday that Dassey, 27, must remain imprisoned while the state challenges a ruling that his confession in the 2005 rape and murder of photographer Teresa Halbach was coerced by investigators.
"It is ordered that the motion to lift the stay is denied," the Seventh Court of Appeals said, according to WBAY.
Last week, a three-judge panel in the same appelate court upheld an earlier ruling that Dassey was intimidated into saying he played a role in the killing of Halbach.
Two of the judges concurred with Judge William Duffin's ruling last year that investigators offered Dassey, then 17, false promises and used his poor IQ to secure a confession — without a parent or attorney present.
"When considered in conjunction with all relevant factors, most especially Dassey's age, intellectual deficits, and the absence of a supportive adult, rendered Dassey's confession involuntary" under the Constitution, Duffin wrote.
In addition, the appeals court gave the state 90 days to retry Dassey. While his attorneys were hopeful he would be immediately released, he must now remain in prison.
Halbach vanished on Halloween in 2005 after an appointment at the Avery family’s salvage yard in Manitowoc County. Her car and charred remains were found on the property several days later.
After fingering Avery for the murder, police turned their attention to Dassey when he was mentioned as his uncle's alibi.
Dassey was sentenced to life in prison. In a separate trial, Avery was also sentenced to life.
Making a Murderer, the 10-part docuseries that premiered in 2015, chronicled a decade of the Avery case, including Dassey’s interrogation, trial and conviction.
Following the documentary's release, the Manitowoc County Sheriff’s Office received an onslaught of public criticism for its handling of the Halbach murder.
The sheriff’s department said that within a month of the show's premiere, it received as many as 300 phone calls and hundreds of emails, most of which were negative, about its role in the Avery case.
A second season of Making a Murderer is expected to run later this year.