Dassey, 26, and Avery, 54, were convicted in separate trials in 2007 of murdering Teresa Halbach two years earlier. They were both sentenced to life in prison.
Their convictions came a few years after Avery spent 18 years behind bars for a sexual assault he didn't commit and for which he was exonerated by DNA evidence in 2003.
Avery later filed a $36 million lawsuit against Manitowac County, Wisconsin; its former sheriff, Thomas Kocourek; and its former district attorney, Denis Vogel.
In 2005, just as Avery was in the middle of the lawsuit related to his wrongful 1985 rape conviction, he was arrested for the murder of Halbach. His suit was settled in 2006 for $400,000, according to the Associated Press.
His lawsuit and the timing of his arrest and conviction in the Halbach case fueled suspicions among some viewers of "Making a Murderer" that Avery was framed for her murder, a notion that former Wisconsin state prosecutor Ken Kratz, who was involved in the case, strongly disputes.
Evidence presented by prosecutors against Avery included that Halbach’s remains were found on his property along with Halbach’s car, which was spattered with his blood, and Halbach’s car key was found in his home with his DNA on it.
Kratz told ABC News in January that the makers of the documentary left out some information on the case against Avery.
"If some of the evidence that was selected ... didn't fit with the narrative ... that Mr. Avery was the product of a conspiracy ... it's my belief that the filmmakers just wouldn't include that information," Kratz said.
"Making a Murderer" filmmakers previously told ABC News that they disagreed with Kratz's assessment that they left out key elements to create a pro-Avery misrepresentation.
"It would be impossible for us to include all the evidence that was presented in the trial," director and executive producer Laura Ricciardi said. “That’s called a trial. What we made was a documentary
And on Friday, after Dassey's conviction was overturned, Ricciardi along with director and executive producer Moira Demos released a statement saying, "Today there was a major development for the subjects in our story and this recent news shows the criminal justice system at work. As we have done for the past 10 years, we will continue to document the story as it unfolds, and follow it wherever it may lead."
After Avery was convicted along with Dassey in the Halbach murder, he was sent back to prison to serve a life sentence without the possibility of parole.
Dassey's conviction was overturned Friday after a judge said in court documents obtained by ABC News that investigators' four-hour interrogation was littered with leading statements and "false promises."
The court documents also noted that Dassey was only 16 at the time of his confession with a "below average intellectual ability," and lacked having "the benefit of an adult present to look out for his interests."
According to Dassey's attorney Laura H. Nirider, the state has the option to appeal or retry the case within 90 days. If the state pursues neither course of action, Dassey will go free, according to court documents.
Zellner told an ABC News affiliate in January that since Avery's conviction in 2007, there have been significant advances in forensic testing that could be used to challenge his conviction.
"The clearest way to do this is with scientific testing and that’s what we will be asking to do," Zellner told WBAY-TV in January.
Zellner has been tweeting since Dassey's conviction was overturned.
"Justice for Brendan as another LE fabricated confession bites the dust," she tweeted Friday, apparently using "LE" to refer to law enforcement. "Convicting the innocent foiled by unbiased court.@MakingAMurderer."
Zellner added in another tweet: "Brendan's opinion shows cops made up crime story. Steven's will show cops made up crime evidence."
Manitowoc County Sheriff Robert Hermann, who was not the sheriff at the time of Avery and Dassey’s arrests, has told ABC's "Nightline" that he is firm that his office's deputies did nothing inappropriate with evidence in the Halbach case.
Back in February, Zellner tweeted: "Fifth trip to Steven Avery. Collected samples for new tests. The inevitable is coming--he was smiling so were we. #MakingAMurderer #Science."
Zellner added two months later, "6th Trip: SA to undergo most advanced testing in world to show his innocence. 'Truth never damages a cause that is just.'"
ABC News reached out to former prosecutor Kratz following the court ruling overturning Dassey's conviction, but hasn't received a response yet.