(CBS 58 / AP) Brendan Dassey's conviction has been overturned the conviction on Friday. 

Dassey will be released from custody in 90 days of the date of the decision unless the State initiates proceedings to retry him.

Dassey was in prison for the murder of Teresa Halbach along with his uncle Steven Avery.

The court decided Dassey's confession involuntary under the Fifth and Fourth Amendments.

U.S. Magistrate Judge William Duffin in Wisconsin said in Friday's ruling that investigators made false promises to Brendan Dassey by assuring him "he had nothing to worry about."

Dassey confessed to helping his uncle Steven Avery carry out the rape and murder of Halbach, but attorneys argued that the confession was coerced. Dassey was 16 when Halbach was killed in 2005.

Duffin says the "repeated false promises, 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 U.S. Constitution.

Making a Murderer was based on this case. 

Renowned Defense Attorney Alex Flynn likened the decision to a lightning bolt.

His live interview on the CBS 58 News at 4 is attached to this story.