“Yes, go on to that.”
“Well, there, sir, I really did my best to put you on the right track. I told you that Meadows was murdered by the same person who killed Mrs. Vane, and because he’d seen the first murder done, I told you that, and I told you that it must have been someone who had access to aconitine. You said just now you thought I meant Dr. Vane, but I didn’t of course; I meant the girl. And then the funny thing is you thought I was trying to pull your leg. Why, it’s all been staring you in the face. I’ve heard you with my own ears talking with Mr. Walton about how funnily Miss Cross was behaving, wanting to go over to France one minute and stay here the next and all the rest of it; and all you thought was that it was nerves. So it was, but not the kind you meant!
“And I’d given you another hint long before that, when I told you there was real bad blood in that family. I told you straight out they were practically all of them criminals; and still you thought she couldn’t be, just because she had an innocent face. Of course the first thing I’d done was to have the records searched for her at the Yard, and found her in them too. Never actually been in prison, you understand, but mixed up before she came here with a very shady crew indeed; a house she got a job in as a parlourmaid was burgled for instance, and another where she was supposed to be the governess; we never laid our hands on the lot that did it but there’s no doubt that she was in with them, though nothing could be proved against her. Oh, and several other things too. She was a bad lot all right before she ever came here, but clever—oh, yes, clever enough.”
“Go on to the second case,” said Roger feebly.
The inspector paused and marshalled his ideas. “Well, now, there, sir, you made a very bad mistake indeed,” he said with some severity. “You jumped to the conclusion that Meadows was killed by aconitine in his tobacco. If you’d troubled to read up aconitine as you ought to have done, you’d have found out that it’s a vegetable alkaloid, and vegetable alkaloids lose all their power if they’re burnt. You can smoke as much aconitine in your tobacco as you like, and it isn’t going to do you any harm.”
“But that’s what killed him,” Roger protested.
“Oh, no, it isn’t, sir, if you’ll pardon me. He was killed by aconitine placed in his pipe, not his tobacco. Aconitine was put in the bowl or the stem of his pipe, sir, where his saliva melted it, and he swallowed it before he knew what he’d done. And that not only proves that it couldn’t have been put there three weeks before, as you thought, but must have been during the previous night, but also that it was put there by someone who knew a little about poisons but not very much, for otherwise there’d have been none wasted in the tobacco. She meant to make sure of the job all right, by the way; there was enough of the stuff there to kill a hundred people.”
“But wait a minute!” Roger interrupted. “You’re wrong there, Inspector. It could have been put there by Mrs. Vane. I found out that Meadows only smoked his pipes a week at a time, remember!”
The inspector’s expression was more pitying than chagrined. “Yes, but did you find out when he changed them, Mr. Sheringham, sir? I did, you see. On Sunday mornings. So it couldn’t have been Mrs. Vane after all. It was somebody who came during that previous night, while he was asleep. It wasn’t the doctor, because he’d never have put the stuff in the tobacco; there’s no conceivable reason why it should have been Miss Williamson; it must have been Miss Cross. But there again there’s no absolute proof.”
“Well,” said Roger, “I’ll be damned!”