Duke Behnke, and Alison Dirr

Post Crescent

A key scene in the wildly popular "Making a Murderer" series focused on the moment defense attorney Jerome Buting found a vial of Steven Avery's blood with a pinhole in the top.

It looked like a turning point for the defense.

The attorneys alleged that Avery's blood, which was found in murder victim Teresa Halbach's car, had been planted — and could have come from that vial kept in the Manitowoc County Clerk of Courts office.

But an FBI agent testified that it wasn't the case, dealing a serious blow to Buting's argument that the blood had been planted.

Years later, Buting still doesn't trust the FBI's test method or its results.

“It was rushed, the whole methodology was rushed,” Buting told USA TODAY NETWORK-Wisconsin. “It had never been validated by any other outside lab. To my knowledge it still never has been.”

The possibility of proving the blood was planted still offers a glimmer of hope for a new trial.

"That would be a complete game changer," Buting said. He couldn't imagine how a judge wouldn't allow a retrial.

The blood in question was found in Halbach's Toyota RAV4. She was murdered in 2005, and Avery and his nephew Brendan Dassey were convicted in 2007 of killing the 25-year-old photographer. The two men were sentenced to life in prison. Both have appealed their convictions.

Their cases have been back in the spotlight since the Netflix docu-series "Making a Murderer" was released in mid-December. Many viewers concluded that Manitowoc County sheriff's officers planted Avery's blood in Halbach's vehicle.

The FBI and the State Crime Lab were involved in analyzing biological evidence used to convict Avery.

The FBI quickly developed a procedure to test samples of blood found in Halbach's SUV for the presence of a preservative called EDTA. That was critical because if EDTA was found in the blood, it would show the blood wasn't from a fresh wound. It would bolster the critical defense assertion that the drops came from the sample of Avery's blood discovered in an unsecured box kept with files from Avery's 1985 erroneous sexual assault conviction.

Neither the FBI nor the State Crime Lab will say anything about the test, including whether it has improved since Avery's 2007 trial.

That's a particularly important question for Buting.

"You certainly don't want to use up whatever sample is left if the science hasn't developed enough and yet maybe could be sometime in the future," Buting said.

DAILY NEWSLETTER: Sign up for "Making a Murderer" updates

Marc LeBeau, head of the FBI's chemistry analysis section, testified during the 2007 Avery trial that the blood in the SUV didn't show any presence of EDTA, so it didn't come from the vial of Avery's blood found inside the clerk of courts office, which is located next door to the Manitowoc County Sheriff's Department.

A defense witness, lab auditor Janine Arvizu, testified EDTA might have been present in the blood but might have been below the detection limit of the FBI's test.

Buting said it was possible that there could have been EDTA in the bloodstains that the test couldn’t detect. But the defense was not able to get the test independently verified because there were no labs capable of running the test.

The FBI declined to comment on whether its EDTA test still is in use today, whether it has been refined or whether it has been replaced by a different test.

"We are not commenting on the Avery case; Dr. LeBeau’s testimony is public record," FBI spokesman Christopher Allen wrote in an email.

The State Crime Lab also wouldn't divulge whether it is playing a role in the Avery or Dassey cases today.

"There isn’t anything we are able to share with you regarding the Avery or Dassey cases at this time, as they are both currently in the appeals process," Anne E. Schwartz, spokeswoman for the Wisconsin Department of Justice, wrote in an email to USA TODAY NETWORK-Wisconsin.

Kelly L. Wouters, the laboratory director at Armstrong Forensic Laboratory in Arlington, Texas, said he had a defense attorney ask his lab last year to test a bloodstain for EDTA.

“We don’t do EDTA testing but we’ve been asked about it in the past,” Wouters said. “We couldn’t find a good method for doing it and what methods there are we don’t have the equipment for.”

Wouters said testing for EDTA isn’t common.

TIMELINE: History of the Steven Avery case

RELATED: “Making a Murderer” coverage, archived stories and more

In his experience, the necessary equipment is usually found in university laboratories but not as much in commercial or crime laboratories.

Having watched the documentary, Wouters said he wanted to know more about the techniques the FBI used and what their data looked like. But he said that the speed with which the FBI developed the test — in just weeks while Avery's trial was ongoing — was not in itself a red flag for him.

“To me that’s plausible,” he said. “Sometimes, if we get asked to develop a new method or bring something new online, it’s possible to get that done in a couple weeks if you dedicate the time to it.”

Buting said he has received emails from scientists across the world about improvements in the science for chemical detection and ideas about other kinds of tests that could be just as useful — or maybe more so — than an EDTA test.

He declined to go into detail, saying he has not researched the ideas or whether they would work in this case. That decision would be up to Avery’s new appeal attorneys, anyway.

Wouters’ lab doesn’t usually work with bodily fluids, but he said he wouldn’t be surprised if techniques have become more exact over time.

“Science marches on,” he said.

Duke Behnke: 920-993-7176, or dbehnke@postcrescent.com; on Twitter @DukeBehnke. Alison Dirr: 920-996-7266 or adirr@gannett.com; on Twitter @AlisonDirr