“I quite agree with you, sir. But we’ve no evidence that he is going to die. His friends sent for you, and you treated him skilfully and left him in a fair way to recovery. That’s all that we really know about it. Yes, I know,” the officer continued as I made signs of disagreement, “you think that a crime is possibly going to be committed and that we ought to prevent it. But you overrate our powers. We can only act on evidence that a crime has actually been committed or is actually being attempted. Now we have no such evidence. Look at your statement, and tell me what you can swear to.”

“I think I could swear that Mr. Graves had taken a poisonous dose of morphine.”

“And who gave him that poisonous dose?”

“I very strongly suspect⁠—”