three o’clock
Suppose Cayley had killed Mark , either purposely , in sudden passion , or accidentally , meaning only to knock him down . Suppose that this had happened in the passage , say about two o'clock , either because Cayley had deliberately led him there , or because Mark had casually suggested a visit to it . -LRB- One could imagine Mark continually gloating over that secret passage . -RRB- Suppose Cayley there , with the body at his feet , feeling already the rope round his neck ; his mind darting this way and that in frantic search for a way of escape ; and suppose that suddenly and irrelevantly he remembers that Robert is coming to the house at three o'clock that afternoon -- automatically he looks at his watch -- in half an hour 's time ... . In half an hour 's time . He must think of something quickly , quickly . Shall he bury the body in the passage and let it be thought that Mark ran away , frightened at the mere thought of his brother 's arrival ?