3 o'clock
Marie and Sauverand guilty : of that there is not the least doubt . But , outside that , absolute mystery . `` Nobody will know nor ever will know anything . In a few weeks ' time , when the two criminals are irrevocably doomed , when the letters are in the hands of the police , on the 25th , or , rather , at 3 o'clock on the morning of the 26th of May , an explosion will destroy every trace of my work . The bomb is in its place . A movement entirely independent of the chandelier will explode it at the hour aforesaid . `` I have just laid beside it the drab-cloth manuscript book in which I pretended that I wrote my diary , the phials containing the poison , the needles which I used , an ebony walking-stick , two letters from Inspector Vérot , in short , anything that might save the culprits .