The Vatican revealed yesterday that its former ambassador to the Dominican Republic is facing charges of posessing child pornography, in addition to the sexual abuse of minors.
Vatican officials found underage porn while investigating Josef Wesolowski, who was placed under house arrest earlier this week to prevent "possible evidence tampering".
He is only the second person to be arrested in this way in recent history. The first was Pope Benedict's former butler, Paulo Gabriele, subsequently sentenced to 18 months in prison for leaking private documents. It is the first Vatican arrest of a high-ranking prelate involved in child sex abuse.
Polish-born Wesolowski, former Nuncio in the Dominican Republic, was recalled to the Vatican a year ago and investigated for sex abuse allegations.
In June, the first stage of his canonical trial ended with him being found guilty of child sex abuse and laicisation, or defrocking, by the Congregation for the Doctrine of the Faith. He appealed against the decision. This week the Vatican began criminal proceedings against him, placing him under house arrest during the trial rather than in custody because of concerns about his health.
Wesolowski, aged 66, was arrested at the Vatican with the permission of Pope Francis, who had received a personal appeal from the United Nations Committee Against Torture in Geneva to intervene.
Vatican spokesman Fr Frederico Lombardi said: "This arrest is due to the express will of the Pope." He said the case was "serious and delicate" and must be addressed without delay and "with the right and necessary rigor, with full assumption of responsibility on the part of the institutions that are part of the Holy See."
Wesolowski was ordained priest in 1972 by the then Archbishop of Krakow, Cardinal Karol Wojtyla, who became Pope John Paul II. He entered the Church's diplomatic service and was ordained bishop in 2000.
Vatican sources said the arrest signals the present Pope's "zero tolerance" approach to child abuse.
Among the allegations against the former nuncio is he sexually abused teenage boys in Santo Domingo, the capital of the Dominican Republic, and paid boys for sex and to masturbate. The case against the former career diplomat reached a new crisis at the end of August this year when the New York Times published an investigation into his abuses, including testimonies from his victims of activities such as sex "bought" in exchange for medicine.
Il Corriere, the Italian newspaper, linked the arrest to last year's enquiry by the UN Committee Against Torture, which last May in Geneva robustly condemned the Vatican for failing to counter child sex abuse by Catholic priests. The newspaper said the Vatican's treatment of Wesolowski constituted a litmus test of the willingness of the Vatican to punish abuse.
Last July the Vatican amended its criminal code, introducing the crimes of torture and pedophilia for the first time.
At that point the Vatican had made it known that Wesolowski no longer enjoyed diplomatic immunity, meaning the Dominican Republic and Poland could proceed criminally against him. After Pope Francis gave the go-ahead, the Vatican exercised its own new penal code to bring him to justice in a criminal trial. It will be the first sex abuse trial in Vatican City and Wesolowski could go to prison for up to 12 years.
Pope Francis has described child sex abuse as an "ugly crime" comparable to "a Satanic Mass".