about twelve o'clock
It is a question of inference . '' `` Explain . We know your powers . '' `` Well , I take it for granted that he killed her -- we must not mince matters -- about twelve o'clock ; for after that hour , the servants told Lina , there was quiet in the drawing-room . Next , I conjecture , he went upstairs to change his clothes : he could not go forth on the world in an evening suit ; and the housemaid says his black coat and trousers were lying as usual on a chair in his dressing-room -- which shows at least that he was not unduly flurried . After that , he put on another suit , no doubt -- WHAT suit I hope the police will not discover too soon ; for I suppose you must just accept the situation that we are conspiring to defeat the ends of justice . '' `` No , no ! ''