VATICAN CITY — In an undisclosed location here, the Vatican authorities are busy questioning Paolo Gabriele, the pope’s butler, and others in a widening leaks scandal that has made the seat of the Roman Catholic Church appear to be a hornet’s nest of back-stabbing and gossip.

Across town, in the lobby of a fancy hotel on the Via Veneto, Gianluigi Nuzzi, the investigative reporter whose new book based on some of the leaks has sent the Vatican into a tailspin, was holding court and looking rather pleased.

‘I’m serene, I’m tranquil, convinced that I did my work in a correct way, without raising questions about the Holy Father,