Melbourne, Australia (CNN) One of the most powerful men in the Roman Catholic Church was found guilty of multiple historical child sex offenses at a secret trial in Melbourne in December, the existence of which can only now be revealed.

Australian Cardinal George Pell, 77, is almost certain to face prison after a jury found him guilty of one charge of sexual penetration of a child and four charges of an indecent act with or in the presence of a child in the late 1990s.

The conviction of Pell, the Vatican treasurer and a close adviser to Pope Francis, will send shockwaves through the church, which is already reeling from accusations of sexual abuse committed by priests worldwide.

Pell is the most senior Catholic official to be found guilty of child sex offenses to date. His conviction brings the escalating international controversy around the abuse of children in Catholic institutions straight to the doors of the Holy See.

A court order banning media reporting of Pell's five-week long trial, which began in November 2018, was lifted by Chief Judge Peter Kidd on Tuesday.

The prosecution's case hinged on the testimony of one man, who said Pell sexually abused him and another boy in Melbourne's historic St. Patrick's Cathedral after mass one Sunday.

Pell arrives at court in Melbourne on Tuesday.

The second victim later died from a drug overdose having never revealed the abuse to anyone. The surviving accuser can not be identified under Australian law governing sex abuse victims.

In court the accuser told the jury how Pell, then Archbishop of Melbourne, discovered the two choirboys drinking wine in the priest's sacristy, a small room at the back of the cathedral.

He claimed Pell forced one of the boys to perform oral sex on him and performed an indecent act on his friend. One month later, the victim said Pell pushed him up against a wall and groped his genitals.

Gasps were heard in court after Pell was pronounced guilty of all charges in December.

In a statement Tuesday, Pell's accuser said he had struggled with "shame, loneliness (and) depression" after the abuse.

"Like many survivors it has taken me years to understand the impact upon my life. At some point we realize that we trusted someone we should have feared and we fear those genuine relationships that we should trust," he said in a public statement from his lawyer.

St Patrick's Cathedral in Melbourne where Pell sexually abused the two boys in the late 1990s.

Under Australian law, all details of the first trial, including its existence, were suppressed due to concerns they could prejudice future juries.

The court order was lifted after the crown prosecutor chose to not proceed with a planned second trial into further child sex allegations against Pell.

Pell has repeatedly maintained his innocence. His legal team confirmed on Tuesday they had filed an appeal against the guilty verdict.

The Vatican said Pell's conviction was "painful news, which we are aware has shocked many people, not only in Australia."

In a statement, it said the Holy See had "maximum respect for the Australian judicial authorities ... We now await the outcome of the appeal process, remembering that Cardinal Pell has reiterated his innocence and has the right to defend himself until the final grade of judgment."

Pope Francis quietly removed Pell from his small council of advisors for "reasons of advancing age" in December, before the news of the cardinal's conviction became public.

The conviction comes as the Vatican is taking tentative steps to make amends for decades of abuse by clergy across the world.

At a historic child abuse summit in Vatican City Sunday, Pope Francis described pedophile priests as "tools of Satan."

Pell makes a statement at the Holy See Press Office, Vatican City on June 29, 2017 after being charged with historical child sex offences.

Stunning testimony

For more than 20 years, the boy at the center of the allegations held a secret he said he was too shocked and scared to disclose.

The attack happened over a period of just six minutes, as hundreds of parishioners were milling outside after Sunday mass.

Pell's attorney Richter said only a "mad man would attempt to rape boys" at such a time. But the victim told the court that's exactly what happened.

Testifying in a video link to the court during a closed session, he described how after mass the boys slipped away from the procession and into the back of the cathedral where they drank some communion wine.

Suddenly Pell appeared and demanded to know what they were doing.

"He planted himself in the doorway and said something like, 'What are you doing in here' or 'You're in trouble' ... Then he undid his trousers or his belt," the surviving accuser told the jury in a closed session.

Crown prosecutor Mark Gibson later read his testimony to a full court, detailing how Pell cornered the pair, pulled aside his robes and pulled out his penis. The then-Archbishop physically forced one of the boys to perform oral sex on him.

According to the accuser's testimony, Pell then instructed him to take off his pants and touched the boy's genitals while masturbating.

The victim said one month later Pell pushed him up against a wall and groped his genitals.

"I didn't tell anyone at the time because I didn't want to jeopardize anything. I didn't want to rock the boat with my family, my schooling, my life ... I had no intention back then of telling anyone ever," Gibson said, quoting the victim's testimony.

Pell's lawyer Richter argued strongly the attack was impossible. He said the boys couldn't have run off without being seen and Pell would have been talking to parishioners after the service.

Richter even said the archbishop's robes couldn't be loosened in the manner described by the accuser. "(This is an) embellishment on a fantasy," he told the jury.

The cardinal never took the stand in his own defense but a video of his meeting with Australian detectives in Rome in 2016 was played to the court.

In the video, Pell said the charges were "the products of fantasy." When asked whether he'd forced a boy to perform oral sex he said it was a "deranged falsehood."

"What a load of absolute and disgraceful rubbish. Completely false. Madness," he told detectives.

Pell looked shocked when the "guilty" verdict was read out on December 11 after the jury had deliberated for three and a half days.

It was the second time Pell had faced court on this set of charges. An earlier, unreported trial in August had resulted in a hung jury after almost six days of deliberations.

Pell is due to be sentenced at a separate hearing in March.

Cardinal George Pell officiates the opening mass of World Youth Day (WYD), in Sydney on July 15, 2008.

Pell's rise and fall

Pell's conviction is a stunning fall of grace for a man who once ran the Catholic Church in Australia with an iron fist.

A powerful and influential figure in his home country, his longtime friend former Australian Prime Minister Tony Abbott praised him as a "fine man" in 2017 before his trial.

Born in the Australian country town of Ballarat, Pell quickly rose through the Catholic Church after being ordained in 1966.

He was made Archbishop of Melbourne by Pope John Paul II in 1996. While in the post, Pell created a program to respond to the increasing tide of sexual abuse allegations against priests.

But Pell's "Melbourne Response" program was criticized for capping compensations to victims at just tens of thousands of Australian dollars. There were allegations people were advised not to go to the police.

In 2014, Pell moved to Rome after he was handpicked by Pope Francis to serve as treasurer of the Vatican and become one of nine advisers on the Council of Cardinals to the Pope.

But Pell's fortunes began to sour after the Australian government announced a Royal Commission into Institutional Child Sex Abuse in 2012.

The damning report by the commission in 2017 found 7% of Australian Catholic priests abused children over the past six decades.

Cardinal George Pell's name on the honor boards of his old school in Ballarat, St Patrick's College. It will be struck off with a black line following his conviction.

Pell appeared as a witness at the commission by video from Rome in a fiery questioning session, which led the cardinal to declare one repeated offender's child abuse "wasn't of much interest to (him)."

In June 2017, it was announced Pell himself would be charged by Australian police on "multiple historical sexual offenses."

In a statement Tuesday, Pell's former school, St Patrick's College in Ballarat, announced they would be striking the cardinal's name from their honor boards with a black line.

"The black line above stands as both a symbol of respect for the bravery of victims and survivors of child sexual abuse and their families, and for the College's deep remorse for the pain and suffering caused by the actions of this individual," principal John Crowley said before the conviction was public.