A computer technician has gone on trial in the Vatican City charged with aiding and abetting the Pope's former butler in stealing papal documents.
Claudio Sciarpelletti has been accused of helping Paolo Gabriele leak the confidential documents while working in the Vatican's Secretariat of State.
Mr Sciarpelletti's lawyer argued that his client has no case to answer and the trial should be dropped.
Gabriele was given an 18-month prison sentence by the same court last month.
He admitted passing documents to a journalist, but said he did it out of love for the church and the Pope.
The former butler is serving his sentence in a special detention room inside the Vatican's police station, amid talk that he may be pardoned by Pope Benedict XVI.
Mr Sciarpelletti, 48, handled secret communications in the Vatican's Secretariat of State, the nerve centre of the Roman Catholic church.
His lawyer said an anonymous tip-off led Vatican police to search Mr Sciarpelletti's desk last May - finding an envelope addressed to Gabriele containing copies of sensitive documentation that had been leaked to the Italian media.
During his brief arrest, he is said to have given confused and contradictory explanations to investigators.
Defence lawyer Gianluca Benedetti denied the claims that the former butler and Mr Sciarpelletti had been good friends, and said his client had been in an "emotional state" in his interviews with investigators.
The Vatican has since said he played a "marginal" role in the scandal.
Senior Vatican communications officer, Greg Burke, said that although Mr Sciarpelletti was being charged with aiding and abetting Gabriele, it was "more like an obstruction charge" relating to his contradictory testimony, the Associated Press reports.
However, the judge refused Mr Benedetti's request to drop the trial, and said the next hearing would be scheduled for Saturday. Analysts say his trial is likely to be shorter than Gabriele's which lasted for a week.
Interest in the case centres on who the witnesses called to give evidence may be, correspondents say. A senior cleric and two top Vatican security officials are expected to be called, as well as Gabriele himself.
It is thought the trial may shine a light on the extent to which other Vatican employees, including clerics, may have been involved.
Much of the stolen information ended up in a best-selling book by journalist Gianluigi Nuzzi about corruption, scandals and infighting at the Vatican.
Gabriele confessed to taking the papers, but said he believed the Pope was being manipulated, and that he hoped to reveal alleged corruption at the Vatican.
The Vatican authorities have limited press access to Mr Sciarpelletti's trial and no TV cameras were allowed in court.