The police now set themselves to close investigation. The porter was certain that nobody had entered the rooms that morning who had not afterwards left. He was sure that nobody had entered unobserved, and he was sure that Mr. Deacon had re-entered his chambers unaccompanied. Working, therefore, on the assumption that the murderer could not have entered by the front door, the police turned their attention to the back door and the windows. The door to the back staircase was locked, and the key was in the lock and inside. Therefore they considered the windows. There were but three of these that looked upon the street, two in one room and one in another, but these were shut and fastened within. Other rooms were lighted by windows looking upon lighting-wells, some being supplied with reflectors. All these windows were found to be quite undisturbed, and fastened within, except one. This window was in the bedroom, and, though it was shut, the catch was not fastened. The porter declared that it was Mr. Deacon's practice invariably to fasten every shut window, a thing he was always very careful about. Moreover, the window now found unfastened and shut was always left open a foot or so all day, to air the bedroom. More, a housemaid was brought who had that morning made the bed and dusted the room. The window was opened, she said, when she had entered the room, and she had left it so, as she always did. Therefore, shut as it was, but not fastened, it seemed plain that this window must have given exit to the murderer, since no other way appeared possible. Also, to shut the window behind him would be the fugitive's natural policy. The lower panes were of ground glass, and at least pursuit would be delayed. The window looked upon a lighting-well, and the concreted floor of the basement was but fifteen or twenty feet below. Careful inquiries disclosed the fact that a man had been at work painting the joinery about this well-bottom. He was a man of very indifferent character--had in fact "done time"--and he was employed for odd jobs by way of charity, being some sort of connection of a member of the firm owning the buildings. He had, indeed, received a good education, fitted to place him in a very different position from that in which he now found himself, but he was a black sheep. He drank, he gambled, and finally he stole. His relatives helped him again and again, but their efforts were useless, and now he was indebted to one of them for his present occupation at a pound a week. The police, of course, knew something of him, and postponed questioning him directly until they had investigated a little further. It might be that Mr. Deacon's death was the work of a conspiracy wherein more than one had participated. II