He was already familiar with most of the evidence: he knew what each witness was likely to tell before one or other entered the box. Bunning came next after himself; Bunning had nothing new to tell. Nor was there anything new in the medical evidence given by Dr. Wellesley and Dr. Barber--all the town knew how the Mayor had been murdered, and the purely scientific explanations as to the cause of death were merely details. More interest came when Hawthwaite produced the fragment of handkerchief picked up on the hearth of the Mayor's Parlour, half-burnt; and when he brought forward the rapier which had been discovered behind the bookcase; still more when a man who kept an old curiosity shop in a back street of the town proved that he had sold the rapier to Wallingford only a few days before the murder. But interest died down again while the Borough Surveyor produced elaborate plans and diagrams, illustrating the various corridors, passages, entrances and exits of the Moot Hall, with a view to showing the difficulty of access to the Mayor's Parlour. It revived once more when the policeman who had been on duty at the office in the basement stepped into the box and was questioned as to the possibilities of entrance to the Moot Hall through the door near which his desk was posted. For on pressure by the Coroner he admitted that between six and eight o'clock on the fateful evening he had twice been absent from the neighbourhood of that door for intervals of five or six minutes--it was therefore possible that the murderer had slipped in and slipped out without attracting attention. This admission produced the first element of distinct sensation which had so far materialized. As almost every person present was already fairly well acquainted with the details of what had transpired on the evening of the murder--Peppermore having published every scrap of information he could rake up, in successive editions of his _Monitor_--the constable's belated revelation came as a surprise. Hawthwaite turned on the witness with an irate, astonished look; the Coroner glanced at Hawthwaite as if he were puzzled; then looked down at certain memoranda lying before him. He turned from this to the witness, a somewhat raw, youthful policeman. "I understood that you were never away from that door between six and eight o'clock on the evening in question?" he said. "Now you admit that you were twice away from it?" "Yes, sir. I'm sorry, sir, I clean forgot that when--when the superintendent asked me at first. I--I was a bit flustered like." "Now let us get a clear statement about this," said the Coroner, after a pause. "We know quite well from the plans, and from our own knowledge, that anyone could get up to the Mayor's Parlour through the police office in the basement at the rear of the Moot Hall. What time did you go on duty at the door that opens into the office, from St. Laurence Lane?" "Six o'clock, sir."