Superintendent Battle said slowly:
“First of all, I’ll say this. As far as the actual murder of Mr. Shaitana goes, I’m not a penny the wiser. There’s no hint or clue of any kind to be found in his papers. As for the four others, I’ve had them shadowed, naturally, but without any tangible result. No, as M. Poirot said, there’s only one hope—the past. Find out what crime exactly (if any, that is to say—after all, Shaitana may have been talking through his hat to make an impression on M. Poirot) these people have committed—and it may tell you who committed this crime.”
“Well, have you found out anything?”
“I’ve got a line on one of them.”
“Which?”
“Dr. Roberts.”
Mrs. Oliver looked at him with thrilled expectation. “As M. Poirot here knows, I tried out all kinds of theories. I established the fact pretty clearly that none of his immediate family had met with a sudden death. I’ve explored every alley as well as I could, and the whole thing boils down to one possibility—and rather an outside possibility at that. A few years ago Roberts must have been guilty of indiscretion, at least, with one of his lady patients. There may have been nothing in it—probably wasn’t. But the woman was the hysterical, emotional kind who likes to make a scene, and either the husband got wind of what was going on, or his wife ‘confessed.’ Anyway, the fat was in the fire as far as the doctor was concerned. Enraged husband threatening to report him to the General Medical Council—which would probably have meant the ruin of his professional career.”
“What happened?” demanded Mrs. Oliver breathlessly.
“Apparently Roberts managed to calm down the irate gentleman temporarily—and he died of anthrax almost immediately afterwards.”
“Anthrax? But that’s a cattle disease?”
The superintendent grinned.
“Quite right, Mrs. Oliver. It isn’t the untraceable arrow poison of the South American Indians! You may remember that there was rather a scare about infected shaving brushes of cheap make about that time. Craddock’s shaving brush was proved to have been the cause of infection.”
“Did Dr. Roberts attend him?”
“Oh, no. Too canny for that. Daresay Craddock wouldn’t have wanted him in any case. The only evidence I’ve got—and that’s precious little—is that among the doctor’s patients there was a case of anthrax at the time.”
“You mean the doctor infected the shaving brush?”
“That’s the big idea. And mind you, it’s only an idea. Nothing whatever to go on. Pure conjecture. But it could be.”
“He didn’t marry Mrs. Craddock afterwards?”
“Oh, dear me, no, I imagine the affection was always on the lady’s side. She tended to cut up rough, I hear, but suddenly went off to Egypt quite happily for the winter. She died there. A case of some obscure blood poisoning. It’s got a long name, but I don’t expect it would convey much to you. Most uncommon in this country, fairly common among the natives in Egypt.”
“So the doctor couldn’t have poisoned her?”
“I don’t know,” said Battle slowly. “I’ve been chatting to a bacteriologist friend of mine—awfully difficult to get straight answers out of these people. They never can say yes or no. It’s always ‘that might be possible under certain conditions’—‘it would depend on the pathological condition of the recipient’—‘such cases have been known’—‘a lot depends on individual idiosyncrasy’—all that sort of stuff. But as far as I could pin my friend down I got at this—the germ, or germs, I suppose, might have been introduced into the blood before leaving England. The symptoms would not make their appearance for sometime to come.”
Poirot asked:
“Was Mrs. Craddock inoculated for typhoid before going to Egypt? Most people are, I fancy.”
“Good for you, M. Poirot.”
“And Dr. Roberts did the inoculation?”
“That’s right. There you are again—we can’t prove anything. She had the usual two inoculations—and they may have been typhoid inoculations for all we know. Or one of them may have been typhoid inoculation and the other—something else. We don’t know. We never shall know. The whole thing is pure hypothesis. All we can say is: it might be.”
Poirot nodded thoughtfully.
“It agrees very well with some remarks made to me by Mr. Shaitana. He was exalting the successful murderer—the man against whom his crime could never be brought home.”
“How did Mr. Shaitana know about it, then?” asked Mrs. Oliver.
Poirot shrugged his shoulders.
“That we shall never learn. He himself was in Egypt at one time. We know that, because he met Mrs. Lorrimer there. He may have heard some local doctor comment on curious features of Mrs. Craddock’s case—a wonder as to how the infection arose. At some other time he may have heard gossip about Roberts and Mrs. Craddock. He might have amused himself by making some cryptic remark to the doctor and noted the startled awareness in his eye—all that one can never know. Some people have an uncanny gift of divining secrets. Mr. Shaitana was one of those people. All that does not concern us. We have only to say—he guessed. Did he guess right?”