Making a Murderer subject Steven Avery wins motion to appeal: 'This evidence has potential to undo the whole case'

Avery's attorney Kathleen Zellner celebrates the development

Steven Avery, the subject of the Netflix documentary Making a Murderer, has won a motion to appeal – a development hailed by a lawyer as a “big win” in his case.

The motion means that a Wisconsin circuit court will now re-examine the case, as Avery’s attorney Kathleen Zellner claims some evidence has been mishandled by authorities.

Avery, a native of Manitowoc County, Wisconsin, is currently serving a life sentence for the murder of Teresa Halbach, which he says he did not commit.

The motion to appeal, filed by Zellner on Avery’s behalf, makes mention of bones found in a gravel pit, which Zellner wants to be tested to check whether the bones are Halbach’s.

If so, Zellner alleges this would challenge the version of events presented by authorities, according to which Halbach’s remains were buried on Avery’s property.

According to the motion filed by the attorney, the bones were returned to Halbach’s family without being tested for DNA.

Now that the motion has been granted, Avery’s team can submit evidence related to the bones.

The circuit court can grant a new trial, or the case can continue in appellate court, which can also grant a new trial or even reverse the conviction, Zellner told Newsweek.

“Either way, the State opposed this motion and lost,” Zellner added.

“This evidence has the potential to undo the whole case, so it is a big win.”

The attorney tweeted on Monday: "We are going to have an extraordinary number of constitutional violations when we are done. The [court of appeals] is letting us create an avalanche of evidence in this record. Higher courts rule."

The story of Avery's conviction was brought to worldwide attention when Netflix released its documentary series Making a Murderer in December 2015.

A second season followed in October 2018.