A court in Argentina has sentenced a Roman Catholic bishop to four and a half years in prison for sexual abuse of two former seminarians in a major blow to Pope Francis, who had initially defended the bishop.

Gustavo Zanchetta, 57, was convicted on Friday of “simple, continued and aggravated sexual abuse”, with his offense aggravated by his role as a religious minster.

A court in the north-western town of Orán, where Zanchetta, 57, was bishop from 2013 to 2017, ordered his immediate detention.

The conviction in the pope’s homeland hits at Francis’s personal credibility since he had initially rejected accusations against Zanchetta, and created a job for him at the Vatican that got him out of Argentina.

Francis has defended his handling of the case, insisting that Zanchetta “defended himself well” when confronted with the first allegations that he had pornographic images on his cellphone.

Francis also defended the decision to give him a job in one of the most sensitive Vatican offices, the treasury that manages the Holy See’s investments and assets, saying Zanchetta had been prescribed psychological retreats each month in Spain and it didn’t make sense for him to return to Argentina between each session.

Following the verdict, the bishop, wearing a face mask, was removed from the court in a car, though it was not clear where he was taken.

Local authorities began to investigate after the allegations emerged publicly in early 2019, when the newspaper El Tribuno de Salta reported complaints about Zanchetta’s conduct as bishop in Orán, about 1,600km (900 miles) north-west of Buenos Aires.

Five priests made a formal accusation before church authorities against the bishop in 2016, accusing him of authoritarianism, financial mismanagement and sexual abuse at the Saint John XXIII Seminary.

The court heard evidence from two complainants, one of whom claimed the bishop had made approaches towards him and asked for “massages”.

Prosecutor María Soledad Filtrín Cuezzo told the court on Thursday that investigators had established the truthfulness of witnesses against the bishop, citing their internal logic, context and precise details.

Zanchetta had flown back to his home country from Rome to face the charges. He has denied the charges and said he is victim of revenge by priests in Orán with whom he had differences.

The pope had ordered a church trial into the case, though the results of that are not known.

Carlos Lombardi of the Network of Survivors of Ecclesiastical Abuse in Argentina – and a representative of victims in the case – said the sentence was “a strong blow” to the pope “because of the public defense he has made in this case …they now have no arguments to protect these criminals in cassocks,” he added.