John Ferak

USA TODAY NETWORK-Wisconsin

MANITOWOC, Wis. — Is Steven Avery's high-profile post-conviction lawyer Kathleen Zellner all bluster?

It's been 17 months since the suburban Chicago lawyer took Twitter by storm. She vowed to prove Avery's innocence in the Oct. 31, 2005, death of Teresa Halbach and unveil the real killer. Her law firm continues to solicit online donations for the Steven Avery Legal Defense Fund to help pay for Avery's defense.

Over the past two years, Zellner, who has 175,000 followers on Twitter, has made a number of bold declarations that have yet to materialize.

Here's a sampling:

Jan. 2, 2016: "Whoever deleted Teresa Halbach cellphone calls is either the murderer or part of cover up. Either way the killer is free."

May 9, 2016: Zellner posted a photo of exonerated former inmates hugging their mothers on Mother's Day. "Steven Avery needs to be in next year's photo - plan to make that happen."

July 5, 2016: "If you think we are just tweeting ... think again. A tsunami of new evidence is on the way."

Jan. 17, 2017: "Not 1 but 8 plants: bullets, bones, blood, camera, cellphone, PDA, key, car + false confession. World's best experts on it."

But the court of public opinion and a court of law are two different universes.

Zellner has yet to file a post-conviction petition on behalf of Avery, who turns 55 in July. He remains in prison, insisting he is innocent.

"The prediction that he'd be out by Mother's Day is slim to none," said Rob Bellin, a Neenah attorney who has closely followed the Halbach murder case over the years.

Read more:

'Making a Murderer:' Where are they now?

Ex-prosecutor Ken Kratz: Don't believe 'Making a Murderer'

USA TODAY NETWORK-Wisconsin reached out to Zellner late last week for comment regarding her predictions about the case and the criticism she has received from Avery supporters for not filing her long-awaited post-conviction motion in Manitowoc County court.

"Next time you hear from me will be when I file Steven Avery's motion," Zellner wrote in her e-mail response. "I could care less what Steven Avery's supporters think. They have absolutely no comprehension of the procedural and forensic complexity of this case."

Zellner did not specify when she plans to file the motion.

The last significant legal filing on Avery's case was last Nov. 23. That's when she and the Wisconsin Attorney General's Office reached an agreement for independent scientific testing on nine items of evidence from the Halbach murder investigation.

"Mr. Avery will present his third party theory in his post-conviction petition that he will file once he obtains the new test results," Zellner wrote in her legal briefs last August.

Johnny Koremenos, director of communications for the state justice department, said "we have been informed that testing on the agreed upon evidentiary items is nearly complete."

Koremenos added that the state has "reason to believe that the defense will file a new motion within the next 45 to 60 days."

Zellner previously told USA TODAY NETWORK that the independent scientific testing should be finished in March.

On March 18, she tweeted, "To all the skeptics, doubters & haters just be patient because we are really going to make you mad." Zellner did not again tweet about Avery's case until last Friday, when she posted this: "Would not still be rep. SA if the test results proved his guilt. Winning takes a little longer than losing."

In her e-mail last week to USA TODAY NETWORK-Wisconsin, Zellner said "this is not a simple DNA case where I submit samples and await the results."

"My only obligation is to Mr. Avery," Zellner wrote. "My predecessors all failed because they did not do a thorough and comprehensive job. I will not be making the same mistake."

Some are questioning her strategy in making such bold statements on social media.

"People have been kind of still waiting for what we thought we would be getting last summer, last August, and we still don't even have a motion or a brief," said Matthew J. Haiduk, a veteran criminal defense attorney in Chicago's western suburbs.

"I'm hoping she's busy," Haiduk said. "You've said all you've had to say on Twitter. It is sort of unfortunate that the sales job seems to be obscuring what is probably very good lawyering. It's going to take some sort of evidence that was not available at that (2007) trial and being able to point to someone else who may have committed the crime."

Others wonder whether Zellner's strategic decision to seek the court's permission last August to conduct the independent scientific testing did not pan out as she hoped, leaving her in a tough spot in trying to regain Avery's freedom.