Andy Thompson

USA TODAY NETWORK-Wisconsin

Lt. Mark Wiegert chooses his words carefully when it comes to Steven Avery’s conviction in the 2005 murder of Teresa Halbach.

“We stand by the integrity of the investigation,” Wiegert, a longtime Calumet County officer who played a central role in the Halbach case, said in an interview with USA TODAY NETWORK-Wisconsin.

Wiegert declined to address specifics about the explosive case — including a series of allegations raised by Avery’s attorney, Kathleen Zellner, in a Newsweek article last week. She said investigators failed to adequately do their job and overlooked key evidence that pointed to Avery's innocence. He also refused to discuss the Brendan Dassey case, in which he assisted in getting a confession from the defendant, who is now serving a life term for his role in Halbach’s slaying.

Wiegert cited an ongoing federal appeal in the Dassey case in declining comment, but he did make it clear in the interview with USA TODAY NETWORK-Wisconsin that Avery’s conviction and subsequent life sentence were justified.

“Mr. Avery was judged by a jury of his peers and was found guilty," he said. "The case has been looked at … by the appeals court and they have upheld everything that was done.”

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In the Newsweek story, Zellner, who has granted few media interviews, said she is focusing on multiple aspects of Halbach’s murder and is planning to pursue new forensic tests.

“They used forensic science to convict (Avery) and I’d be using it to convict them of planting evidence,” Zellner told Newsweek.

Zellner must produce compelling new evidence to the appellate court to have an opportunity to vacate the verdict and exonerate Avery. The case is the focus of the highly popular “Making a Murderer” docu-series on Netflix.

In an earlier interview, former Wisconsin Supreme Court Justice Janine Geske said there is a high standard for new evidence that can alter a conviction. It goes well beyond criticism on social media that Avery and Dassey were treated poorly by the criminal justice system, she said.

“People don’t understand that you don’t just set aside a verdict like that without a substantial reason — and not just feelings,” Geske said.

Andy Thompson: 920-996-7270 or awthompson@gannett.com; on Twitter @Thompson_AW