“If you were to search all England,” said he, “I don’t suppose you could find a household more self-contained or freer from outside influences. Whole weeks would pass, and not one of them go past the garden gate. The professor was buried in his work and existed for nothing else. Young Smith knew nobody in the neighbourhood, and lived very much as his employer did. The two women had nothing to take them from the house. Mortimer, the gardener, who wheels the Bath chair, is an army pensioner - an old Crimean man of excellent character. He does not live in the house, but in a three-roomed cottage at the other end of the garden. Those are the only people that you would find within the grounds of Yoxley Old Place. At the same time, the gate of the garden is a hundred yards from the main London to Chatham road. It opens with a latch, and there is nothing to prevent anyone from walking in.

“Now I will give you the evidence of Susan Tarlton, who is the only person who can say anything positive about the matter. It was in the forenoon, between eleven and twelve. She was engaged at the moment in hanging some curtains in the upstairs front bedroom. Professor Coram was still in bed, for when the weather is bad he seldom rises before midday. The housekeeper was busied with some work in the back of the house. Willoughby Smith had been in his bedroom, which he uses as a sitting-room, but the maid heard him at that moment pass along the passage and descend to the study immediately below her. She did not see him, but she says that she could not be mistaken in his quick, firm tread. She did not hear the study door close, but a minute or so later there was a dreadful cry in the room below. It was a wild, hoarse scream, so strange and unnatural that it might have come either from a man or a woman. At the same instant there was a heavy thud, which shook the old house, and then all was silence. The maid stood petrified for a moment, and then, recovering her courage, she ran downstairs. The study door was shut and she opened it. Inside, young Mr. Willoughby Smith was stretched upon the floor. At first she could see no injury, but as she tried to raise him she saw that blood was pouring from the underside of his neck. It was pierced by a very small but very deep wound, which had divided the carotid artery. The instrument with which the injury had been inflicted lay upon the carpet beside him. It was one of those small sealing-wax knives to be found on old-fashioned writing-tables, with an ivory handle and a stiff blade. It was part of the fittings of the professor’s own desk.

“At first the maid thought that young Smith was already dead, but on pouring some water from the carafe over his forehead he opened his eyes for an instant. ‘The professor,’ he murmured - ‘it was she.’ The maid is prepared to swear that those were the exact words. He tried desperately to say something else, and he held his right hand up in the air. Then he fell back dead.