It was announced at the weekend that Josef Wesolowski was under criminal investigation as a citizen of the Holy See.
If Vatican prosecutors proceed with the case, Archbishop Wesolowski faces the prospect of an unprecedented sex-abuse trial in a Vatican court and even imprisonment in the city state's tiny jail.
The case will be a major test for the Pope, who has announced he plans to set up a committee to try to remedy the problem of child abuse by Catholic clergy.
Not only was Archbishop Wesolowski an official representative of the Pope, he was also ordained a priest and bishop by his fellow Pole, John Paul II, who is to be made a saint in April.
Archbishop Wesolowski was recalled to Rome from his post as papal nuncio in the Dominican Republic in August after a television expose accused him of hiring teenage "rent boys".
The NCDN channel alleged the Vatican ambassador was known as "Jusepe" among the boys who frequented a known pick-up area in the Plaza de Montesinos in the capital, Santo Domingo.
A 13-year-old shoeshine boy said Archbishop Wesolowski paid him several times to masturbate while filming him on his mobile phone.
The boy alleged that the nuncio sometimes took up to five boys together to a house where he masturbated them.
The program showed the Vatican diplomat walking along the waterfront in the area, drinking a beer by himself.
A second Polish cleric in the Dominican Republic, Father Wojciech Gil, a friend of the former nuncio, faces similar allegations, which he denies.
The Vatican has refused to disclose the whereabouts of Archbishop Wesolowski since his recall. The church says, however, that he is "at the disposition of his superiors".
As a former papal nuncio and a citizen of the Holy See, Archbishop Wesolowski has diplomatic immunity and cannot be extradited from the Vatican City State.
He faces two investigations, one canonical and one criminal. Canon law convictions can result in defrocking while breaches of the Vatican's criminal code can carry jail terms.