“But Walter Brooklyn, who rang up his club from Prinsep’s rooms at 11.30, was back at his club before midnight. That leaves very little time. If the theory you advance is true, how do you fit in the times? George Brooklyn could hardly have got back into the garden and got himself killed, before a quarter to twelve. It would take Walter Brooklyn five minutes to get out of the house and back to his club. That leaves less than ten minutes for Prinsep to go up to his room and for Walter Brooklyn to murder him.” “That sequence of time is difficult; but it is not impossible. Crime is usually a pretty rapid business. Probably Walter and George came back into the garden together, and the two murders followed in rapid succession. Prinsep killed George, and he and Walter went upstairs together. Then Walter killed him while they were discussing his affairs. You remember the papers I found lying on the table?” “Perhaps, but that seems to me exceptionally quick work—so quick that my instinct is to doubt whether it is the right explanation. After all, there is no direct evidence that Walter Brooklyn did murder Prinsep.” “Surely the walking-stick and the telephone message together are very strong evidence?” “Not strong enough, I am certain, to obtain a conviction. The telephone message was sent some time before George Brooklyn was killed. And don’t forget that, a moment ago, you thought your evidence that Walter Brooklyn had murdered George Brooklyn equally strong. Yet already you are practically convinced that he did not.” “I am still convinced that he was there when the murder took place in the garden.” “Ah, that is another matter. He may have been present at both murders, and yet committed neither.” “I see now what you are driving at. You mean that there may be a fourth man involved?” “That may be so; but I was not quite sure on that point. What the evidence seems to me to establish beyond reasonable doubt is that some meeting of the three men—Prinsep and George and Walter Brooklyn—took place at Liskeard House that night. That meeting was followed by—probably resulted in—the death of two of the three. There may have been others present. That is for you to find out. But I am clear that the next step is to discover what this meeting was about, and who was there. If we knew that, it would probably throw a new light on the whole situation.” “In the circumstances, there is still, it seems to me, every reason for arresting Walter Brooklyn. He was certainly present, whether he committed murder or not.” “I think it will be best to leave him at large for the time being. We have, I think, ample evidence of his presence in the house, but not of his having had a guilty hand in the murders. I think, instead of arresting him, it will be far better for you to see him, and find out all you can about what happened that night.” “Very well. I will try to see him at once. Ought I to warn him that what he says may be used against him?”