“Meanwhile, we'd come to a blank end with the Fleetwoods and had turned to Billingford. My impression was that he seemed genuinely surprised by the news of Staveley's murder; but he might have been acting, for all one could tell. What we did get out of him was the general impression that Flatt's cottage was inhabited by a gang of rogues. How many were there? Three, if one took Billingford at face value; four, if one believed the story the claimant blurted out when we questioned him at the cottage.
“Anyone could see that the fourth man was a dark horse. He might be the murderer whom they were shielding, possibly. But there was another explanation of his disappearance; he might be someone well known to the local people, and whom it was desirable to keep under cover. How would that fit in with things? Suppose the claimant was an impostor; he wouldn't be very anxious to meet the villagers more than he could help, for fear of dropping on someone who might trap him and expose him. The less he saw of his neighbors the better; and his disfigurement gave him a fair excuse for keeping indoors in the daytime. Staveley was well enough known to the villagers also; and perhaps he had good reason for not wishing his presence known. If the fourth man was in the same boat, then none of them would care to go shopping and so forth, and yet supplies had to be got daily. Hence it might be convenient to have a man like Billingford as the nominal host, to act as go-between for them in their public transactions. That's how it appeared to me. Naturally, I was curious about the fourth man, and I got you, inspector, to set a watch and see if he could be recognised.
“That left me with a fair suspicion that these fellows were hatching some devilment or other at the cottage. Then I noticed the card-index; and I saw light to some extent. A card-index implies the need for ready reference. The claimant, if he were a fraud, would need to cram himself with all the available facts about the doings of the real Derek Fordingbridge—just as Arthur Orton crammed up all the facts about Roger Tichborne. And a card-index would be the handiest repository of all the news they could collect. As you saw for yourself, squire, that guess of mine was right.
“Assume that state of affairs—I had no certain knowledge then—and things begin to fall into their places. I've given you my notion of why Billingford was needed. What about the other three?
“The claimant was obviously needed to represent Derek Fordingbridge; and he'd been cast for the part on two grounds. First, his face was so much damaged that no one could swear to his original appearance. He might quite well have been Derek or anyone else, so far as that went. Then the loss of his fingers made him invaluable also, because he couldn't be expected to write like the real Derek nowadays, with a mutilated hand. All that was wanted in addition was a good memory to cram up the immense amount of facts that they needed in order to meet questioning.
“Then there was Staveley. What was he doing in the affair? Well, obviously, he had a lot of information about the Foxhills people which he must have picked up while he stayed there with the real Derek on leave, and also some more facts which he must have learned from Mrs. Fleetwood from time to time.
“And, finally, there was the fourth man. I suspected that he might turn out to be a second information-mine; and when I heard the report you gave me, inspector, about the fishermen and Sapcote having recognised him as an ex-valet at Foxhills, I felt I was getting on to fairly sure ground.
“Well, there were four of them to share in the loot if they pulled it off. But a third's better than a quarter-share any day. If they had pumped Staveley dry of his information, and had got notes of it all on that card-index, what further need had they for friend Nicholas? None whatever.
“And suppose they could involve the Fleetwoods in a murder case and get them hanged, wouldn't that remove one possible set of objectors to the claimant dropping into the funds? So I didn't exclude the possibility that they knew—although they denied it—that Staveley was going to meet Mrs. Fleetwood at Neptune's Seat that night. When I say ‘they,’ I really mean the faceless fellow and Aird.
“There was a further long shot possible. I'm not sure if it really entered into their plans; but I give it you for what it's worth. Suppose they suggested a walk along the sands to Billingford that evening, and arranged matters so that he would reach the rock just after the murder had been committed and they had cleared out. Wouldn't that have been a tight corner for Master Billingford? With any luck he might have been hung for the murder, since he'd no evidence but his own to rely on to prove he wasn't on the spot when the shot was fired. And then there would be only two of them, instead of four, to share out the loot if they got it.