Pope Francis has become the first Pope to publicly denounce a 'culture of abuse and cover-up' within the Catholic Church.
Francis wrote a letter to Chilean followers on Thursday saying he was ashamed that victims of a pedophile priest who operated with impunity in the country for decades were ignored for so long.
'With shame I must say that we didn't know how to listen or respond in time,' he wrote before adding: 'Never again.'
Pope Francis said he is ashamed that the Catholic Church helped to cover up sexual abuse by pedophile priest Fernando Karadima in Chile, vowing 'never again'
Father Fernando Karadima was first accused of abusing teenage boys in Chile in 1984 and despite the claims being found credible by church officials, no action was taken against him.
Instead his victims were ignored or discredited by the bishops they had relied upon to protect them.
In 2010 four of the accusers went public and in February 2011 the Vatican found Karadima guilty of sexually abusing minors and psychological abuse.
He was forced into retirement, banned from acting as a priest for the rest of his life, and moved away from his former parish - though he still lives in Chile.
However, a statute of limitations on the crimes means he will never be criminally prosecuted. He continues to deny guilt.
The case made international headlines this year after Francis accused Karadima's victims of committing slander and defended Bishop Juan Barros, who was accused of covering up for him.
The Pope's letter was released on the eve of another weekend he will spend listening to Karadima's victims.
The letter was issued on the same day the Vatican announced its top abuse investigators were returning to Chile on a new mission.
In the eight-page letter, Francis once again thanked victims for their 'valiant perseverance' in denouncing abuse and searching for the truth 'even against all hopes or attempts to discredit them.'
'The 'never again' to the culture of abuse and the system of cover-up that allows it to perpetuate requires us to work together to generate a culture of care,' in the way we relate to one another, power and money, he said.
No other pope has publicly spoken of a culture of cover-up in the church.
Catholic Priest Juan Ignacio Gonzalez, spokesman for Chile's Episcopal Conference,