"Well, this is the way I decided Charters must have gone to work:
"He'd determined to kill Hogenauer to keep Hogenauer's mouth shut. Oh, quite cold-bloodedly. Maybe he thought he was justified in doin' it; I'm never quite sure how these people with a persecution mania, who think nobody appreciates 'em, are likely to act. But here was the snag: He was the Chief Constable. He was bound to investigate the murder he meant to commit himself. And Hogenauer had a small circle of intimates. And Charters didn't want any of 'em blamed for it. He was tryin' to be a weird and wonderful thing, which is exactly like Charters if you see him as I see him: he was tryin' to be a murderer like a gentleman. Do you understand torture? If not, you'll never understand Charters. He wanted nobody blamed. In particular, he didn't want the Antrims blamed-"
"Even though," put in Evelyn, very thoughtfully, "he stole poison from them?"
"Even then, I think," said H.M. "But listen. What he wanted was a dummy motive and a dummy murderer-somebody against whom a devilish good case could be made out, but who still couldn't be caught. And he remembered Hogenauer bein' in the Intelligence Service years ago. He also remembered L. who was at once cloudy and solid. If the whole Secret Service couldn't catch L. or find out who he was in the past, small blame would attach to Charters's constabulary if they failed to find him now. Charters had no idea where L. was; he supposed nobody had. L. was the man for his money. But in order to make clear the leerin' dangers of L. to all concerned, he had to bring in somebody who knew about 'em: in short, he had to bring in me. And, d'ye know, I'm rather wonderin' if it didn't tickle something under Charters's ribs: if it didn't give him a deep, sharp feelin' of satisfaction; when he sat there and spun that yarn about L., just to see whether in one last fling Martin Charters (the shelved one) couldn't make a fool of the old man. And he did.
"He'd got it worked out. Do you remember," H.M. said abruptly, "when I was questionin' Antrim about the famous night when Antrim gave Hogenauer the bromide, Antrim said that Hogenauer suggested bromide himself?
"Yes. Y'see, I'm inclined to think Charters knew a whole lot more about Hogenauer, and Hogenauer's `experiment,' than he admitted. To begin with, long before Charters had any idea of crooked work, long before the Willoughby case broke, he'd heard where Hogenauer was livin'. He was curious. He sent Sergeant Davis to see what the mysterious Hogenauer was up to, and, when he heard about the `lights round the flower-pot' he was still more curious. He wondered whether Hogenauer himself was up to hanky-panky. It looked like it, didn't it?’
"That, I'm inclined to believe, was why he thought he could safely go to Hogenauer with his bag of money, and get Hogenauer's opinion of the stuff. But Hogenauer wasn't having any. `I shouldn't be so holy,' Charters advises; 'considering what you're doing here:' And then poor old Hogenauer, suddenly realizin' that funny interpretations may be put on his conduct (for Keppel has warned him about the mysterious, sinister letters Hogenauer has been writin'), Hogenauer is afraid the police are after him. And he blurts out the truth. Which gives Charters an idea for a neat murder."
Evelyn spoke suddenly.
"I think he was a devil," she said. "'Gives him an idea for a neat murder.' If he'd been an honest murderer, he'd have brained Hogenauer with a poker then and there, and shut his mouth like that. But he didn't. I say, why are you defending him?"
"I said, if people will stop interruptin' me," H.M. went on woodenly, "I'll tell you what happened. Well, Charters promises Hogenauer he won't try to pass off the money as counterfeit; he soothes him down. He takes an interest in the `experiment,' which Hogenauer explains. But then Charters suggests it's pretty dangerous to the health —‘