"By poison," said the third man, who was dark, young, unobtrusive and retiring in manner. "You see this deep scratch on the back of the neck. In that way the poison was administered. I take it that Sir Charles was bending over his desk and the person who committed the crime scratched him with some very sharp instrument impregnated with poison." "Mrs. Brown!" gasped Dan, staring at the heavy, swollen body of his late guardian, whom he had dined with in perfect health. The three men glanced at one another as he said the name, and even the policeman on guard at the door looked interested. The individual in uniform spoke with his cold eyes on Dan's agitated face. "What do you know of Mrs. Brown, Mr. Halliday?" he demanded abruptly. "Don't you know that a woman of that name called here?" "Yes. The secretary, Mr. Penn, told us that Miss Moon induced her father to see a certain Mrs. Brown, who claimed that her son had been drowned while working on one of the steamers owned by Sir Charles. You saw her also, I believe?" "I was in the hall when Miss Moon went to induce her father to see the poor woman. That was about a quarter-past eight o'clock." "And Mrs. Brown--as we have found from inquiry--left the house at a quarter to nine. Do you think she is guilty?" "I can't say. Didn't the footman see the body--that is if Mrs. Brown committed the crime--when he came to show her out? Sir Charles would naturally ring his bell when the interview was over, and the footman would come to conduct her to the door." "Sir Charles never rang his bell!" said the officer, drily. "Mrs. Brown passed through the entrance hall at a quarter to nine o'clock, and mentioned to the footman--quite unnecessarily, I think--that Sir Charles had given her money. He let her out of the house. Naturally, the footman not hearing any bell did not enter this room, nor--so far as any one else is concerned--did a single person. Only when Mr. Durwin----" "I came at nine o'clock," interrupted the baldheaded man imperiously, "to keep my appointment. The footman told Mr. Penn, who took me to Sir Charles. He knocked but there was no answer, so he opened the door and we saw this." He again waved his hands towards the body. "Does Mr. Penn know nothing?" asked Halliday, doubtfully. "No," answered the other. "Inspector Tenson has questioned him carefully in my presence. Mr. Penn says that he brought Sir Charles his spectacles from the dining-room before you left for the theatre with the two ladies, and then was sent to his own room by his employer to write the usual letters. He remained there until nine o'clock when he was called out to receive me, and we know that Mr. Penn speaks truly, for the typewriting girl who was typing Sir Charles's letters to Mr. Penn's dictation, says that he did not leave the room all the time. "May I look at the body?" asked Dan approaching the desk, and, on receiving an affirmative reply from Durwin, bent over the dead.