Colwyn returned to Durrington in a perplexed and dissatisfied frame of mind. The trial, which he had attended and followed closely, had failed to convince him that all the facts concerning the death of Roger Glenthorpe had been brought to light. Really, the trial had not been a trial at all, but merely a battle of lawyers about the state of Penreath's mind. If Penreath was really sane--and Colwyn, who had watched him closely during the trial, believed that he was--the Crown theory of the murder by no means accounted for all the amazing facts of the case. Should he have done more? Colwyn asked himself this question again and again. But that query always led to another one--_Could_ he have done more? In his mental probings the detective could rarely get away from the point--and when he did get away from it he always returned to it--that Penreath, by his dogged silence, had been largely responsible for his own conviction. If a man, charged with murder, refused to account for actions which pointed to him as the murderer, how could anybody help him? Silence, in certain circumstances, was the strongest presumptive proof of guilt. A man was the best judge of his own actions and, if he refused to speak when his own life might pay the forfeit for silence, he must have the strongest possible reason for holding his tongue. What other reason could Penreath have except the consciousness of guilt, and the hope of escaping the consequences through a loop-hole of the law? Colwyn, however, was unable to accept this line of argument as conclusive, so he tried to put the case out of his mind. But the unsolved points of the mystery--the points that he himself had discovered during his visit to the inn--kept returning to his mind at all sorts of odd times, in the night, and during his walks. And each recurrence was accompanied by the consciousness that he had not done his best in the case, but had allowed the silence of the accused man to influence his judgment and slacken his efforts to unravel the clues he had originally discovered. Thus he travelled back to his starting-point, that the conviction of Penreath had not solved the mystery of the murder of Roger Glenthorpe.