CHICAGO — Guessing how federal appeals court judges will rule based on the questions they ask in a hearing is more parlor game than science.

Nevertheless, an attorney for the state of Wisconsin had barely started his argument Tuesday that Brendan Dassey’s murder conviction should be reinstated when Judge Ilana Rovner stopped him cold.

Rovner wanted to know if Dassey, convicted in the 2005 murder of photographer Teresa Halbach, would have concluded he could go home after answering questions by investigators, instead of being arrested. After all, he was a low-IQ, “extremely suggestible” 16-year-old, she noted.

Wisconsin’s deputy solicitor general, Luke Berg, was firm in his response: No specific promises were ever made.

However, the exchange immediately highlighted a critical issue in the case: Even if Dassey wasn’t given an explicit promise of leniency, did the way he was questioned — including lines such as, “The truth will set you free” — produce an involuntary confession?

Don’t you think, Rovner asked Berg, that investigators “crossed the line?”

Rovner, nominated to the court by Republican President George W. Bush, is leading a three-judge panel of the Chicago-based 7th Circuit Court of Appeals. Dassey’s murder conviction, sensationalized in the “Making a Murderer” documentary series, was overturned last August by William Duffin, a federal magistrate judge in Milwaukee. Duffin ruled that Dassey’s constitutional rights were violated because investigators for the prosecution made false promises to Dassey during multiple interrogations.

The state appealed that ruling, which put the case before the federal appeals panel.

Judge Ann Williams, who was appointed to the appeals court by Democratic President Bill Clinton, also wanted to know about why one investigator suggested to Dassey that he was in sort of a father role during the questioning.

Berg maintained that the investigators had acted properly, saying, “I don’t think they were even implied promises.” He concluded by telling the panel that no crucial details confessed by Dassey — including how Halbach pleaded for her life, how she was breathing and the smell of her burned remains — were “fed” to Dassey during the questioning. “None of those memories were planted,” he contended. “They were raw and real.”

Judge David Hamilton seemed to reprove Berg at one point, telling him: “Obviously, there were vague promises of leniency.”

But Hamilton, an appointee of Democratic President Barack Obama, also interrupted Dassey’s lawyer, Laura Nirider, moments after she began her arguments. Nirider spoke of the “drumbeat of promises” from investigators before “every major admission” made by Dassey. She said investigators “overbore” Dassey’s will, getting him to admit to things that didn’t happen.

Hamilton told Nirider he had watched the videotape of Dassey’s interrogations. “I watched the whole thing,” he said. “I don’t see any will being overborn.”

And Hamilton characterized some of the techniques used by the investigators on Dassey as “calling him out” on inconsistencies in his story.

But Nirider argued that “they fed him the answers” they were looking for when he didn’t give them the information they wanted to hear.

More than 100 people attended the oral arguments, which were concluded in less than an hour. Among those present were members of Halbach’s family and Kathleen Zellner, the attorney for Dassey’s uncle, Steven Avery.

The hearing was just one part of the appeal.

In papers filed with the court, Berg argued that Dassey’s confession was not coerced because the prosecutor’s investigators who questioned him never made him any explicit promises. The questioning was marked by the two investigators alternately telling Dassey they were on his side, and pressing him to provide more details of the crime that they insisted they already knew. The Seventh Circuit, he added, “has frequently upheld juvenile confessions where the police applied much more pressure than they did here.”

Duffin countered that the investigators made “repeated false promises” that, “when considered in conjunction with all relevant factors, most especially Dassey’s age, intellectual deficits and the absence of a supportive adult, rendered Dassey’s confession involuntary.” They also argue that the confession was based on the investigators feeding facts to him.

There is no timetable for the panel to issue their ruling, but it could take months.

If the judges decide that Dassey was unfairly convicted, the state will have to decide whether to put him on trial again. For now, Dassey has remained in prison.

Dassey and Avery were convicted in separate trials of the 2005 murder of Halbach. The charred remains of the 25-year-old photographer were found outside of Avery’s Manitowoc County home. Both are serving life terms in prison, although Dassey will become eligible for parole.

The case was the subject of “Making a Murderer,” a 10-hour Netflix series that became an unexpected hit after it was released in December 2015.

Avery was convicted largely on the basis of physical evidence, including blood, that contained his or Halbach’s DNA. No physical evidence implicated Dassey.