He sat down on one of the chairs to consider his next step. There were three lines of inquiry open to him, and he hesitated as to that on which to begin. First, there was the general investigation, the interviewing of the servants, Lady Ponson, Miss Enid, and any others from whom he might gain information, the examination of Sir William’s papers, the tracing of his movements for some time previous to his death, the consideration of his finances, the ascertaining whether anyone might benefit by his death—all routine details, each step of which was suggested by his training, and his experience in similar cases. This work he knew he would have to carry out some time, and obviously the sooner it was done the better. Next came the testing of Austin’s alibi. Though he had made a beginning with this, a great deal remained to be done before he could feel satisfied as to its truth. And satisfied he must be. The circumstances were too suspicious for anything less than utter certainty to suffice. As he turned the matter over in his mind he slowly came to the conclusion that he could work on these two points simultaneously. The same information would, to some extent at least, be required for both, and the same people would have to be interviewed. But there was a third point which, equally urgently, required attention. The man who had made the fifth line of footsteps must be traced. And here, again, no time should be lost in getting to work. Tanner felt he could not take on this inquiry with the others. There was work in it alone for another man. He therefore decided he would wire for an assistant to whom he could hand over this portion of the case. But as he was here he might as well begin the interviewing of the Manor servants. He therefore left the boathouse, and walked slowly up to the terrace under the great trees of the lawn, past long herbaceous borders, and through the Dutch garden with its geometrically shaped beds, its boxwood edgings, and its masses of rich colour. Approached from the front, the old house looked its best. Though somewhat heavy and formal in detail, its proportion was admirable, and it had an air of security and comfort strangely at variance with the tragic happening which had overtaken its owner. Tanner labelled it one of the ‘stately homes of England’ as he crossed the terrace to the ornate porch and pulled the bell. Parkes opened the door. The Inspector introduced himself, and courteously asked for an interview. With equal politeness, and an evident desire to help, Parkes brought his visitor to his own sanctum and told his story. But to Tanner most of it was already known. Indeed, on a very few points only did he add to his knowledge of the case.