Foyle leaned over the table, his face set and stern, and gripped her tightly by the wrist. "Do you realise," he demanded, and his voice was fierce, almost theatrical in its intensity, "that you left your finger-prints on the hilt of the dagger with which you killed that man--indisputable evidence that will convict you?" She shuddered away from him, but his hand-grip bruised the flesh of her wrist as he held her more tightly. He had timed his denunciation well. The strain she had put on herself to meet the situation snapped with the sudden shock. For a brief second she lost her head. She struggled wildly to release herself. His blue eyes, alight with apparent passion, blazed into hers as though he could read her soul. "I never left finger-prints," she exclaimed wildly. "I wore gloves.... Oh, my God!" The superintendent's hand opened. The storm of passion on his face died down. The woman, now with a full realisation of what her panic had done, was staring at him in an ecstasy of terror. Green was writing furiously. It was Foyle who broke the stillness that followed. "That will do, I think," he said in an ordinary tone of voice, as though resuming a dropped conversation. "Have you got that down, Green? Mrs. Goldenburg,"--he gave her her real name,--"you will be charged with the wilful murder of your husband. It is my duty to warn you that anything you say may be taken down in writing and used as evidence against you." A hysterical laugh came from the woman's lips. She flung her hands above her head and went down in a heap, while shriek after shriek of wild, uncanny laughter echoed in the room. CHAPTER LIV The blaze of electric lights under their opal shades in Heldon Foyle's office became dim before the growing of the dawn. The superintendent, a cigar between his lips, was working methodically over half-a-dozen piles of papers. At the other side of the table Green puffed furiously at an old brier as he compiled from the documents Foyle handed him a fresh list of witnesses and their statements to be submitted to the Treasury solicitors. All night the two men had toiled without consciousness of fatigue. Their jigsaw puzzle was at last righting itself. The fragments of the picture had begun to shape clearly. Their efforts had at last been justified. That alone would be their reward. The trial would show little of the labour that the case had cost--only the result. The hard labour of many scores of men would never be handled outside the walls of Scotland Yard. They had nothing to do with the guilt or innocence of the Princess Petrovska. When the case was handed over to the Treasury it would be entirely straightened out, and it would be for them to present the simple issue to the judge and jury at the Old Bailey. Foyle flung away the remnant of his cigar, and drew out his watch. It was nine o'clock. Sir Hilary Thornton, who had heard of the woman's confession by telephone, might be expected at any moment.