The Vatican is hunting a suspected mastermind of the "Vatileaks" scandal that has led to Pope Benedict's butler being charged over the leaking of sensitive documents.

Paolo Gabriele, 46, was detained last week but few believe he was the brains behind the leaks.

Investigators are combing his computer and bank details to trace people he has been in touch with. His cellphone is also being examined as many documents allegedly in his possession were photographed while on the pope's desk.

His arrest comes two months after the pope appointed a special commission to investigate the embarrassing leaks.

The documents show how contracts were awarded to favoured companies and also highlight allegations of internal power struggles.

One theory is that Gabriele has been made a scapegoat for senior Catholic figures out to undermine Vatican secretary of state Cardinal Tarcisio Bertone. Another is that the leaking is aimed at the pope's private secretary, Monsignor Georg Ganswein, who has angered many of the Vatican old guard by giving interviews to glossy Italian magazines.

Although the pope made no direct reference to the arrest, he said in his sermon yesterday: "Communication between people is becoming more superficial and difficult. We see daily events in which it appears men have become more aggressive, confrontational. They seem to be concerned only with themselves, their own interests."