"A member of the Willoughby gang," supplied Evelyn.
"Uh-huh. That circumstance should also 'a' told you that Serpos hadn't found out he was stealing counterfeit money.' Oooh, no, my lads. He knew jolly well what he was carrying, as he'd known all along.
"Ken very thoughtfully shoved him into a lavatory, and the next stage of the adventures began. Whack! Straightaway Ken meets a feller," H.M.'s hand appeared past my shoulder and tapped Stone, "who presents tolerably good credentials and tells you L. is dead. But did you doubt Charters's story even then? No. What proof had there ever been, ask again, that Hogenauer ever made a proposition to betray L.? Charters's statement: that's all. Was it made to anyone else? No. Did it sound inherently probable in itself? No. Was there direct evidence that it couldn't have been made? Yes. But it didn't make you suspicious of Charters; it only made you suspicious of Stone.
"By the time you d had your skylarkin' at the Cabot Hotel, and learned the truth about the light-cuff-links-missing-books affair, I was beginnin' to get more than a glimmering of the truth about it myself. And, by the time Ken 'phoned in his second report, I had the whole thing arranged in reasonable order. So far, I'd taken a devilish lot of whacks. I was the clown in the Punch and Judy show: every time I stuck my head up over the stairs, somebody batted it with a club. And the audience roared with mirth. But, remember, my lads: it's only the Clown that survives the Punch and Judy show. I'm used to that. Nobody appreciates me. Bah.
"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 —‘
Stone sat up.
"I've got you," Stone said. "He suggests Hogenauer ought to visit the doctor the night before the experiment for a going-over. He suggests Hogenauer ought to ask the doctor about bromide, and take a bromide before the experiment begins-"
"Sure. They were talkin' about Antrim, dye see, in that back parlour with the door shut. And Bowers, comin' in late and hearin' Hogenauer do so much talkie' about Antrim, thinks it's Antrim who's there.
"It's always the cussedest thing that happens. Those bottles really were switched in the surgery, with fake labels pasted on 'em: Charters arranged it in the evening before Hogenauer got there. He could get in easily through the French window. The trap was all ready.
"But a very revealin' question has been asked in this case. Somebody asked: If the murderer really switched the bottles, why was he so fastidious as to switch 'em back again to their right places? And there you got the answer before you. Because Charters's lop-sided conscience was always stingin' him in an unexpected place; it even stung him after it was dead, the way a wasp can. He could quite coolly arrange to poison Hogenauer. Y'know, I got a suspicion Charters has an idea that foreigners are — well, not exactly not human, but at least that poisonin' a foreigner is slightly less reprehensible an offense than poisonin' a countryman. He could kill Hogenauer. But he couldn't stand the thought that somebody else, somebody he wasn't after, might get a dose out of that bottle. Above all, at Madam Antrim's hands."
"So," put in Evelyn, "during the ten or fifteen minutes while Antrim was out for a stroll after Hogenauer had left, he sneaked in — "
"No!" said H. M. sharply. "That's just what I don't mean. Otherwise there'd have been no mix-up about that sash-window. Think back again. Antrim went for a stroll, yes. The house was open and the lights were on. But where did Antrim say he went for a stroll?"
"On the headland just behind the house," said Evelyn.
"Yes. And so, with the lights on, Charters couldn't get in without bein' seen. And afterwards Antrim locked up the place. But Charters had to get in.’
"He did get in late that night, d'ye see. But somethin' was rackin' him all over again. There were holes in his plan. The bottles had been switched and put back into their places, yes. Hogenauer now had the dose of poison, yes. But suppose nobody noticed that there had been a switch of bottles from a mysterious hand: as he'd intended? Suppose it was simply thought Mrs. Antrim had given poison to Hogenauer, out of the strychnine-bottle, with deliberate intent — as Evelyn did think?"