Disgraced Australian Cardinal George Pell began his last-ditch attempt to have his conviction of child sex assault overturned on Tuesday. He has filed for his final available appeal in Australia's High Court, an official in Canberra said.

Pell, 78, is currently serving a six-year sentence for abusing two choirboys in the 1990s. He has long maintained his innocence of the crimes, which were revealed in 2014 when one victim went to the police after the other passed away due to a drug overdose.

The cardinal was once a Vatican treasurer and part of the College of Cardinals, the group that elects the next pope. He was an outspoken supporter of Catholic orthodoxy, interfaith dialogue, and known as a climate change denier, despite Pope Francis' position on protecting the environment.

He was found guilty on five charges related to the sexual assault in 2018 and was sentenced in March of this year.

Last month he lost an appeal when the state of Victoria's Court of Appeal ruled against him, in a split 2—1 decision. The court said "it was open to the jury to be satisfied beyond reasonable doubt that Cardinal Pell was guilty of the offenses charged," and that it found Pell's accuser to be neither a liar nor delusional.

Australia's High Court may, however, decline to hear his case — a decision process that is likely to take months. Pell is still under investigation by the Vatican, which will result in a decision of whether or not to defrock him.

es/stb (AFP, Reuters)