"That theory is plausible enough on the surface, but only on the surface. For the same reason that establishes Miss Heredith's innocence, the murderer could not have escaped by running down the staircase, because there was not sufficient time to get past the people who had been alarmed by the scream. But if the murderer was a man, it is just possible that he might have darted out of the bedroom and dropped over the balusters, before the dining-room door was opened, getting clear away without being seen by anybody--not even by Miss Heredith. An examination of the staircase of the left wing has convinced me that this feat was possible. The staircase has a very sharp turn in the middle, which has the effect of hiding the top of the staircase from the bottom, and the bottom from the top. The leap is not so dangerous as the one from the window, because it is not so high. It is probably six feet less, allowing for the flooring beneath and the higher window opening above. The spot by the foot of the staircase where the murderer might have dropped is well screened, even from the view of anybody near the bottom of the staircase, by some tall tree shrubs in tubs, and some armour. "But there is another and likelier way by which the murderer might have escaped. I saw the possibility of it as soon as I examined the upstairs portion of the wing in which the murder had been committed. There are several places where the murderer could have hidden until chance afforded the opportunity of escape. He would avoid seeking shelter in any of the adjoining bedrooms, because he would realize that they would be searched immediately the murder was discovered, but there are excellent temporary places of concealment behind the tapestry hangings, or in the thick folds of the heavy velvet curtains at the entrance to the corridor, or in the small press or wardrobe which is built right over the head of the stairs. Suppose that the murderer, after firing the shot, dashed out into the corridor with the idea of escaping down the stairs. He hears the guests coming upstairs, and realizes that he is too late. He instinctively looks round for some place to hide, sees the curtains, and slips behind them. From their folds he watches the guests troop along the corridor to the murdered woman's bedroom. He could touch them as they passed, but they cannot see him. Then, while they are all congregated round the doorway of Mrs. Heredith's bedroom, he emerges on the other side of the curtains, slips down the staircase, and gets out of the house without meeting anybody." "But all the guests did not go upstairs," observed Captain Stanhill, who was following his companion's remarks with close attention. "Some stayed in the dining-room. Tufnell, the butler, made that quite clear when you were examining him this morning."