"It shows him up as a pretty tough specimen," said the detective, astride on a chair with a big black cigar in the corner of his mouth. "He wasn’t going to lose a trick. While he was working for Barker he was gathering all the evidence against his employer that his position in the Whitehall office gave him access to." "Laying his plans for blackmail," said George. "That’s it. He had his eagle eye trained on the future. When Barker and his girl were feeling safe in some secluded corner, these letters—documentary testimony to the plot—could be used as levers to extort more money." "Do you suppose Barker was on to it and decided to get him out of the way before he had a chance to use them?" said Babbitts. "No—I don’t see it that way. There was no indication in the room of a search. I guess Barker acted on the principle that the fewer people share a secret the easier it is to keep." "Looks to me," said George, "as if Ford _had_ made some move that scared the old man. Coming back that way into a house full of people! Considering the circumstances he took a mighty big risk." "Not as big a one as having Ford at large," answered O’Mally. "You’ve got to remember that not one of the three knows the murder has been discovered. They think they’re as safe as bugs in a rug. With Ford out of it the only menace to Barker’s safety is removed. I look at this as a last perfecting touch, the coping stone on the edifice." The chief, who had been silently pacing back and forth across the end of the room, came slouching to the table and picked up the longer of the two letters. Holding it to the light he read it over murmuringly, then dropped it and said: "Curious that a man who had conceived such a plot would allude to it in writing." I spoke up. What seemed to me the first rational words of the meeting gave me my cue. "What makes you so sure the thing alluded to in those letters _is_ the murder?" I was standing back between the window and the table. They all squared round in their chairs to stare at me, O’Mally bending his head to level a scornful glance below the shade of the electric standard. "What else _could_ they allude to?" he said. "I don’t know. Nobody, not a person here, knows all that existed between Barker and Miss Whitehall. There’s no reason to take for granted that the plan, scheme, whatever you like to call it those letters indicate, was the killing of Harland." O’Mally gave an exasperated grunt and cast an eye of derisive question at the chief. It enraged me and my hands gripped together. "Oh, Lord, Jack, you’re nutty," said George. "We know Barker and Miss Whitehall were in love, and we know Barker committed the murder, and we know she helped. That was enough to occupy their minds without going off on side mysteries."