Friday's filing claims police framed Avery, whose trial and conviction served as the focus of the Netflix series
Credit: Netflix

The lawyer for Steven Avery – whose murder trial was the focus of Netflix’s hit docu-series Making a Murderer – has filed a motion seeking more forensic testing of the evidence used to convict him and which he has long claimed was planted, PEOPLE confirms.

Defense attorney Kathleen Zellner’s Friday filing, requesting the testing, echoed Avery’s charge that he was framed.

The filing was made in the Wisconsin Court of Appeals and obtained by PEOPLE. It calls for Avery’s appeal to be stayed until a ruling is made about the requested testing.

In 2007, Avery was sentenced to life behind bars without the possibility for parole for the murder of 25-year-old photographer Teresa Halbach in Manitowoc County, Wisconsin.

But Avery, 54, has always maintained his innocence and claimed that law enforcement officials planted samples of his blood, collected from him during a previous criminal case, in Halbach’s car before it was found five days after her 2005 murder.

Zellner’s filing links Andrew Colborn and James Lenk, of the Manitowoc County Sheriff’s Office, to the discovery of every piece of evidence that Avery has suggested was planted. Zellner asks in the filing that more forensic analysis be done on that evidence, saying that Avery will cover the costs of the additional testing.

The filing calls for “the most comprehensive, thorough, and advanced forensic testing ever requested by a criminal defendant in the State of Wisconsin.”

During the 2007 trial, both Lenk and Colborn denied accusations they planted evidence.

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The filing argues that, since Avery’s 2007 conviction, “considerable progress has been made in forensic DNA methods, procedures and tests, including the development of tests for the specific detection of blood, saliva, semen and urine.”

Zellner also wants “body fluid source testing” done on all of the evidence recovered from Halbach’s vehicle and car keys, to distinguish whether the DNA came from blood, saliva, semen or urine.

At trial, prosecutors said that DNA collected from Halbach’s car had originated from a cut to Avery’s finger. If the source testing ends up revealing that DNA came from another bodily fluid instead, it could undercut the case for Avery’s guilt.

The filing also seeks radiocarbon testing, “which could definitively establish the age of Mr. Avery’s blood found in the victim’s vehicle and determine, based on the age, if the blood was planted.” Zellner also wants trace testing to be done on the car, to determine if chemical solvents were used to remove any DNA.

Interest in Avery’s case skyrocketed following the premiere of the hit Netflix series, which heavily scrutinized the case. (Halbach’s family has slammed the series as “one-sided,” telling PEOPLE they believe Avery is guilty.)

Filming for Making a Murderer‘s second season, following the post-conviction process, began two weeks ago in Manitowoc. It has not been announced when it will air.

Friday’s filing comes two weeks after a federal judge overturned the murder conviction of Avery’s nephew, Brendan Dassey, in Halbach’s death.

Neither a Wisconsin Department of Justice spokesperson nor Zellner immediately returned calls Friday seeking comment.