VATICAN CITY - Paolo Gabriele, the papal butler on trial in the Vatican, told judges that for 20 days he was held in a tiny cell where he could not even fully extend both arms and where Vatican police kept the lights on 24 hours a day.

Gabriele's testimony about the conditions of his detention after his arrest in May came in response to questions posed by his lawyer Oct. 2, the second day of his trial on charges of aggravated theft for allegedly stealing reserved papal correspondence and leaking it to a reporter.

After the testimony, Jesuit Father Federico Lombardi, Vatican spokesman, said the Vatican court had ordered an investigation into the claims.

The Gendarme Corps of Vatican City State, as the Vatican police force is formally known, issued a statement saying that Gabriele was held in a small cell for 20 days while previously scheduled remodeling work was sped up and completed on a larger room for prisoners. The police said the work included improvements "responding to the requirements requested by the Convention Against Torture," a 1984 international agreement, which the Vatican signed.

As for the lights being left on, the police said the decision was made that it was a necessary precaution to ensure that Gabriele did not hurt himself. The statement added, however, that Gabriele was given a sleep mask.

Gabriele's Vatican physician made regular visits, the statement said, adding that Gabriele even told the doctor that he was "resting peacefully" and, in fact, was not as nervous as he had been before his arrest.

Complete meals were delivered to him three times a day, and he ate them in the company of police officers. He was taken outside each day and offered use of the police gym, although he declined that offer. Each day included "moments of relaxation and socialization with personnel from the Gendarme Corps with whom, for obvious reasons," he previously enjoyed a friendship. The officers, like Gabriele, worked together in the Vatican and accompanied the Pope at audiences and on trips.

The police also said Gabriele had "constant contact" with his spiritual advisors; he was escorted to Mass with his family and was able to visit with his family or meet with his lawyers almost any time he wanted.

The police statement said that if the Vatican investigation into the treatment of Gabriele demonstrates that his accusations are unfounded, the police would consider suing him.