Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Australia's highest court has overturned the conviction of Cardinal George Pell, the most senior Catholic cleric ever to be convicted of child sex abuse.

He was sentenced to six years in prison in March 2019, but Monday's ruling will free him.

The High Court found that the unanimous jury that convicted him in 2018 "ought to have entertained a doubt as to the applicant's guilt with respect to each of the offences for which he was convicted," and it ordered that verdicts of acquittal be entered.

Pell was convicted in December 2018 of abusing two choirboys while he was archbishop of Melbourne in the 1990s.

The decision means he was released from Barwon Prison outside Melbourne after having served 13 months of the six-year sentence. Images captured the cardinal being driven from the prison, NBC News partner 7News in Australia reported.

Judgment has been delivered in Pell v The Queen https://t.co/TzjVX0RLXh — High Court of Australia (@HighCourtofAus) April 7, 2020

Pell who has always maintained his innocence said Monday that he had suffered a "serious injustice."

"I hold no ill toward my accuser, I do not want my acquittal to add to the hurt and bitterness so many feel; there is certainly hurt and bitterness enough," he said in a statement to Australian media after the high court's ruling.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

"However my trial was not a referendum on the Catholic Church; nor a referendum on how Church authorities in Australia dealt with the crime of paedophilia in the Church," Pell said in the statement. "The point was whether I had committed these awful crimes, and I did not."

The High Court found that the Court of Appeal of the Supreme Court of Victoria, which upheld Pell's sentence last year, "failed to engage with the question of whether there remained a reasonable possibility that the offending had not taken place."

Pell was convicted of assaulting the 13-year-old boys after he caught them swigging sacramental wine in a rear room of St. Patrick's Cathedral in Melbourne in late 1996. The jury also found Pell guilty of indecently assaulting one of the boys in a corridor more than a month later.

He has denied the allegations.

Cardinal George Pell leaves Melbourne Magistrates' Court on May 1, 2018. Michael Dodge / Getty Images file

Pell was largely convicted on the testimony of one of the choirboys, now in his 30s with a young family. He first went to police in 2015 after the second alleged victim died of a heroin overdose at age 31. Neither can be identified under state law.

Director of Public Prosecutions Kerri Judd told the High Court last month that the surviving choirboy's detailed knowledge of the layout of the priests' sacristy supported his accusation that the boys were molested there.

Pell's lawyers argued that Pell would have been standing on the cathedral steps chatting with churchgoers after Mass when his crimes were alleged to have occurred, that he was always with other clerics when dressed in his archbishop's robes, that he could not have performed the sexual acts alleged while wearing the cumbersome garments and that he could not have abused the boys in the busy priests' sacristy without being detected.

The High Court ruled that unchallenged evidence from a witness was inconsistent with the alleged victim's account, including Pell's practice of greeting congregants on the cathedral steps after Mass and the "continuous traffic in and out of the priests' sacristy" for 10 to 15 minutes after the conclusion of the procession that ended Mass.

Download the NBC News app for breaking news and politics

The High Court found that even if it found the alleged victim's account to be credible, the evidence from the other witness "nonetheless required the jury, acting rationally, to have entertained a reasonable doubt as to the applicant's guilt in relation to the offences involved in both alleged incidents."

The Victoria state Court of Appeal rejected Pell's appeal in August by a 2-1 majority ruling. The High Court decided in November to hear Pell's appeal, which was his last chance to overturn his convictions.

Victoria Police said in a statement that it respected the decision of the High Court "and continue to provide support to those complainants involved."

"Victoria Police remains committed to investigating sexual assault offences and providing justice for victims no matter how many years have passed," police said in the statement, adding that it acknowledged the "thorough work on this case" by task force investigators.

Archbishop Mark Coleridge, president of the Australian Catholic Bishops Conference, said in a statement that the court outcome would be welcomed by those who believed in Pell's innocence, but that it will be "devastating" for others.

Bishops Conference president Archbishop Mark Coleridge has just issued this statement responding to the High Court's judgment pic.twitter.com/0Vv3LdUoL0 — Australian Catholic Bishops Conference (@ACBC1) April 7, 2020

"The result today does not change the Church's unwavering commitment to child safety and to a just and compassionate response to survivors and victims of child sexual abuse," Coleridge said. "The safety of children remains supremely important not only for the bishops, but for the entire Catholic community."

Coleridge said that anyone with allegations should go to the police.