He might have been murdered by some stranger for the sake of his portable property.

This was highly improbable for the same reason: his body could hardly have failed to be identified.
"These three explanations are what we may call the outside explanations.
They touched none of the parties mentioned; they were all obviously improbable on general grounds; and to all of them there was one conclusive answer--the scarab which was found in Godfrey Bellingham's garden.

Hence I put them aside and gave my attention to the fourth explanation.

This was that the missing man had been made away with by one of the parties mentioned in the report.

But, since the reports mentioned three parties, it was evident that there was a choice of three hypotheses, namely: "(_a_) That John Bellingham had been made away with by Hurst; or (_b_) by the Bellinghams; or (_c_) by Mr.Jellicoe.
"Now, I have constantly impressed on my pupils that the indispensable question that must be asked at the outset of such an inquiry as this is, 'When was the missing person last undoubtedly seen or known to be alive ?' That is the question that I asked myself after reading the newspaper report; and the answer was, that he was last certainly seen alive on the fourteenth of October, nineteen hundred and two, at 141 Queen Square, Bloomsbury.