A Vatican computer expert is due in court today in a trial that could shed light on whether Pope Benedict's former butler acted alone in leaking sensitive documents.

Claudio Sciarpelletti is accused of aiding and abetting the butler, Paolo Gabriele, who in October was sentenced to 18 months in jail for aggravated theft.

Sciarpelletti, 48, spent one night in a Vatican jail on May 25, two days after Gabriele was arrested when police searched his home and found many copies of papal documents, some alleging infighting in the papal court and corruption at the highest levels of the Roman Catholic Church.

Gabriele, one of the pope's closest household assistants, admitted leaking the documents to the media in what he said was an attempt to help disclose corruption and "evil" in the headquarters of the 1.2 billion-member faith.

Vatican officials, eager to put the embarrassing episode behind them, say Sciarpelletti's role was marginal and expect the trial to be shorter than that of the former butler, which lasted only four sessions.

Prosecutors had at first considered charging Sciarpelletti with being a direct accomplice to aggravated theft, violation of state secrecy and obstruction of justice, but later lessened their accusations to aiding and abetting.

He faces up to one year in jail but is expected receive a short sentence or a fine.