“Yes; but, if Brooklyn killed Prinsep, it seems he must have done so between 11.15, when Prinsep was still alive, and 11.30, when Brooklyn was seen leaving the house.”
“That does not follow at all. We know he came back after 11.30, since he was found dead in the grounds. The first question is, How and when did he come back?”
“I have made every possible inquiry about that. The front door was bolted at about 11.45, and Winter is positive that he did not come in again that way. There are two other ways into the garden. One is through the coach-yard. That was locked and bolted about 11, and was found untouched this morning. The other is through the theatre. Nobody saw him, and the caretaker says he could not have gone through that way without being seen. But it appears that the door from the theatre into the garden was not locked until nearly midnight, and it is just possible he may have slipped through that way. He seems to have been seen in the theatre earlier in the evening—before his call at Liskeard House at 10.45.”
“Was it a usual thing for Prinsep to walk about the garden at night?”
“Yes, they tell me that he often took a stroll there on fine nights before going to bed.”
The superintendent rubbed his chin thoughtfully. “I can only see one thing for it,” he said. “We have no evidence to show which of these men died first, and therefore, which, if either of them, killed the other. You must follow up both sets of clues until you get further evidence to show which is the right one. But remember that, even if one murder can be accounted for in that way, there is still another murderer somewhere at large—unless another unexpected corpse turns up with clear evidence of having been murdered by one of the other two.”
The inspector laughed. “Well,” he said, “it all seems a bit of a puzzle. It seems to me the next thing is to find out whether either of them had any special reason for murdering the other. If you agree, I shall work up the antecedents of the case, and do a little research into the family history.”
“Yes, that’s probably the best we can do for the present. But spread the net wide. Find out all you can about the whole family and the servants—every one who is known to have been in the house last night—every one who could have any reason for desiring the death of either or both of the murdered men.”
“I suppose one of them must have murdered the other,” said the inspector reflectively.
“I see no sufficient reason for thinking that,” replied his superior. “It looks to me more like a very carefully planned affair, worked out by some third party. But we mustn’t take anything for granted. Your immediate job is certainly to follow up the clues you have found. Even if they do not lead where we expect them to lead, they will probably lead somewhere. A deliberately laid false clue is often just as useful as an ordinary straightforward clue in the long run.”