midnight
So ended the case of Samuel 's diamonds , so far as concerned Samuel himself and the owner ; but the case of the Red Triangle had only begun . THE CASE OF MR. JACOB MASON The mystery of Denson 's death remained a mystery , despite all the police could do . The coroner 's jury returned a verdict of `` Murder by some person or persons unknown '' -- which , indeed , was all that could be expected of them ; for they had no more before them than the bare fact that the body , disguised in the clothes of a labourer , had been found on the steps near the Duke of York 's column , just before midnight , by a police constable . But for the housekeeper 's identification , even the name of the victim would have been unknown . The jury certainly wasted some time in idle speculation as to the strange triangular mark found on the forehead , without a speck of evidence to help them ; but in the end they returned their verdict , and went home . But the police knew a little more than the jury , though that little rather confused than helped them .