ten o'clock in the evening
People formed themselves into groups on the benches and pavements and ate and drank while discussing the matter . A part of the night was spent in this way and nothing happened to reward the patience of the crowd , who began to wonder , somewhat wearily , if they would not do better to go home , seeing that Sauverand was in prison and that there was every chance that the fourth letter would not appear in the same mysterious way as the others . And yet they did not go : Don Luis Perenna was due to come ! From ten o'clock in the evening the Prefect of Police and his secretary general , the chief detective and Weber , his deputy , Sergeant Mazeroux , and two detectives were gathered in the large room in which Fauville had been murdered . Fifteen more detectives occupied the remaining rooms , while some twenty others watched the roofs , the outside of the house , and the garden . Once again a thorough search had been made during the afternoon , with no better results than before . But it was decided that all the men should keep awake .