Could not inquisitors have attempted to suppress or distort information so that their activity would remain hidden from contemporaries and posterity alike? On the contrary, it was strict Holy Office practice to preserve detailed records of all its proceedings from the first summons to the final sentencing. The insistence on the meticulous recording of every word ordered during the trial was intended to discourage the inclination to ask leading questions which would suggest to the accused how they should reply. A permanent member of every inquisitorial court was the notary, who took down in writing every question and every answer, including the exclamations of pain emitted by the victims of torture. Inquisitors did not feel that they had anything to hide. By bringing renegade Christians to punishment-but above all to reconciliation with the Church, they were redeeming offenses committed against God and saving souls for eternal life. […]
This is not to say that inquisitorial worked in public; far from it. Each official took a solemn vow of secrecy, conducted interrogations in strict privacy, and jealously guarded the records of trial proceedings. There were several reasons for this. Witnesses for the prosecution remained anonymous, since they had to be protected from possible retaliation by the family and friends of the accused, not an unknown occurrence. Moreover, once a defendant to name his accomplices, the holy office might have to move swiftly to bring them into custody. Its effectiveness would have been seriously impaired if word of their incrimination leaked out to them before they could be apprehended. And, finally, a reason which may seem unexpected, the reputation of the accused had to be protected.
John Tedeschi, The Prosecution of Heresy (1991)