John Ferak

USA TODAY NETWORK-Wisconsin

Nearly three months after Steven Avery’s post-conviction lawyer pledged she had a plan to overturn her client’s 2007 murder conviction, both sides have signed a written agreement to begin independent scientific testing on several critical pieces of evidence.

The agreement, several weeks in the making, was filed Wednesday with Sheboygan County Circuit Judge Angela Sutkiewicz, the special judge appointed to oversee Avery’s post-conviction appeal. Avery attorney Kathleen Zellner tweeted Wednesday afternoon that it had been signed.

"It's encouraging that the Attorney General's Office was so cooperative and helpful in expediting these tests," Zellner told USA TODAY NETWORK-Wisconsin. "Our experience in our other exonerations is that's the best attitude in working toward trying to discover anything" that gets to the truth.

Avery was convicted of intentional first-degree homicide by a jury of Manitowoc County residents in the death of Teresa Halbach, 25, of rural Calumet County. His case gained international attention when the "Making a Murderer" docu-series debuted on Netflix nearly a year ago.

Practically all of the evidence included in the scientific testing order is connected to Halbach’s blue-green Toyota RAV4. The vehicle was located along the outer ridge of the Avery Salvage Yard on Nov. 5, 2005, six days after Halbach vanished. She was last seen alive on Halloween. She had visited the salvage yard to photograph a red van that Avery wanted to sell through the Auto Trader magazine.

These critical items of evidence will undergo testing as part of this week’s court order:

Blood flakes recovered from the floor near the center console of Halbach’s RAV4.

Bloodstain cutting from the driver’s seat.

Bloodstain cutting from passenger’s seat.

Swab of the RAV 4 ignition area where blood was found.

Swab of bloodstain taken from the rear passenger’s door.

Swab of bloodstain taken from a CD case found in vehicle.

Additionally, three other items of evidence used to secure Avery’s arrest and eventual conviction are subject to the new testing order.

Those items are:

A vial of blood said to be a sample of Avery’s blood from 1996. This was the vial of blood that Avery’s murder trial defense lawyers Dean Strang and Jerry Buting came across during their pretrial case research inside the clerk’s office at the Manitowoc County Courthouse.

A spare key for Halbach’s vehicle found in Avery’s bedroom by Manitowoc County Sheriff’s deputies James Lenk and Andrew Colborn.

The swab from the hood latch of Halbach’s RAV4 that later generated a DNA profile for Avery. Forensic testing on the hood latch was not performed by the Wisconsin State Crime Lab in Madison, even though the lab initially impounded the vehicle and conducted a battery of standard forensic tests. Rather, the swab of the hood latch that yielded the DNA profile of the murder defendant did not occur until six months later. In April 2006, Calumet County sheriff’s officials decided to carry out their own forensic testing of the hood area.

Zellner has said she wants to determine if the hood latch DNA swab was fabricated from other known DNA samples that were in the possession of Calumet and Manitowoc County law enforcement.

John Ferak: 920-993-7115 or jferak@gannett.com; on Twitter @johnferak