SYDNEY, Australia — Cardinal George Pell walked out of prison on Tuesday after Australia’s highest court reversed his 2018 conviction for molesting two choirboys decades earlier — liberating the most senior Roman Catholic cleric to ever face trial over child sexual abuse.

The world may never be able to assess whether the court’s reasoning was sound.

The panel of seven judges ruled that the jury lacked sufficient doubt about the accusations against Cardinal Pell, the former archbishop of Melbourne and treasurer for the Vatican. Jurors, the court argued, ignored “compounding improbabilities” caused by conflicting accounts from the cardinal’s main accuser and other witnesses.

But no one outside the court case can test that comparison. The central evidence — the testimony of the main accuser, on which the case “was wholly dependent,” the judges wrote — has never been released, not in video, audio nor even redacted transcripts.

It is just one glaring example of the secrecy and lack of accountability that have shaped the Pell prosecution from the beginning. No criminal trial in Australia’s recent history has been as high-profile nor as hard to follow and scrutinize.

Cardinal Pell was convicted in December 2018, but the verdict was not reported for two months. The court lifted its gag order only after a second trial involving additional accusations was dropped.

“A problem in this case is that the public mostly couldn’t watch,” said Jeremy Gans, a professor at Melbourne Law School who closely followed the trial. “Most of us didn’t know any of the details, and none of us have seen the complainant’s testimony.”

There was a reason for caution. Australia’s sexual abuse laws require that the identities of child victims be protected — in this case, the main accuser was 13 years old at the time of the alleged abuse in 1996. He came forward in 2015.

But critics question whether the public’s right to know could have been preserved.

“There should be some way of providing the public with access to the transcript in a way that doesn’t reveal the identity of the person so people can judge whether or not to agree,” Mr. Bosland said. “The only way the judicial branch of government is held accountable is through principle of open justice, and that requires that the public be given as much information as possible.”

In its ruling on Tuesday, the High Court essentially decided the criminal case of one of the world’s most powerful religious figures based on how a jury had handled testimony that no one outside the proceedings has been able to assess.

The judges’ order suggested that jurors put too much faith in the main accuser’s account without adequately considering the “unchallenged evidence” of additional witnesses. The prosecution, the order indicated, did not do enough to interrogate those who said the scene following a Sunday Mass 20 years earlier would have been too busy to allow for what was alleged — including the accusation that the cardinal forced his penis into the accuser’s mouth after catching the two choirboys drinking wine in the priests’ sacristy.

But without the testimony of the accuser for comparison, it’s difficult to assess what led the jury to deliver a guilty verdict.

Steven Spaner, Australia coordinator for the Survivors Network of Those Abused by Priests, said that as the trial went on, culminating in acquittal, “it started to look like this was not a fair deal, this was power, this was those who can influence using their influence.”

Cardinal Pell’s prominence has always seemed to hover over the proceedings. Big George, as he was known in his hometown of Ballarat, Australia, carried a domineering mien and management style from his early days in the priesthood through his rapid rise up the ranks.

He was often the public face of the Catholic Church’s response to the abuse scandal. As archbishop of Melbourne, he set up an alternative resolution process for abuse survivors that the Vatican admired, and that many Australians viewed with skepticism. It initially capped payments at 50,000 Australian dollars, or $31,000, with compensation conditioned on victims keeping their traumas confidential.

Many saw him as a protector of finances first, and parishioners second.

“There are a lot of people saying Pell was a scapegoat for the tragedy of this whole thing,” said Peter Wilkinson, a former Catholic priest and researcher in Melbourne. “That’s a reasonable argument. People were angry, extremely angry, and the allegations against George Pell gave then a human target for their anger.”

A statement from the Vatican said Pope Francis “welcomes the High Court’s unanimous decision,” adding that he “has always expressed confidence in the Australian judicial authority.” He offered his morning Mass on Tuesday for those who suffer from unjust sentences.

But for many of those who have been living with the legacy of abuse in the church, the High Court’s decision is a blow to their faith in a justice system they had just started to trust.

Lisa Flynn, a lawyer representing the father of the deceased accuser in a civil claim, said that her client was struggling to understand how the criminal justice system had ultimately “failed both the choirboys” — the one who testified and a second who died before the trial.

She said that the High Court’s decision revealed systemic issues in Australia’s capacity to deal with sexual violence and to trust the verdicts of its citizens.

“The voice of the victims in this matter,” Ms. Flynn said, “haven’t really been heard.”