“Wonderfully,” said Hemingway. “Just as if all the wheels had been oiled—which I don't doubt they had been.”
The Colonel flushed. “You believe that we missed something?”
“Sorry, sir! I do. Mind you, I'm not surprised! You'd none of you any reason to suspect Walter's letter wasn't what it seemed to be. I daresay I wouldn't have started to smell a rat, if I hadn't come upon it amongst Warrenby's own papers, where it had no business to be. It was that which set me thinking.”
“But, good heavens, Hemingway, are you suggesting that Warrenby, acting as Coroner, suspected all along that the letter was a fake?” exclaimed the Colonel, in horrified accents.
“Not all along, no,” replied Hemingway. “I should say it was only when he got to thinking about it more particularly that he began to have his doubts, same like me. Probably after Gavin took up his residence in Thornden, and showed clearly what sort of a neighbour he was going to be. Silly of him to have made an enemy of Warrenby. That was his conceit, of course, thinking he could run rings round anyone he chose. Well, I've got plenty of evidence to lead me to suppose that Warrenby's reaction to the sort of contemptuous way Gavin probably treated him would have been to see if he couldn't get some kind of a hold over him. He'd be bound to think over Walter Plenmeller's death. It was easy for him to go over the inquest again, at his leisure. He may have felt as I do about the letter, or there may be something in it, which I haven't spotted, that struck him as fishy. You can take it he didn't remove it from the file because he wanted a bit of bedtime literature.”
“Do you believe it to be a forgery? I don't set up to be a handwriting expert, but I'd swear to it as Walter's handwriting.”
Hemingway nodded. “Oh, yes, I wasn't questioning that, sir! Do you know if the envelope was preserved?”
“I can't remember that I ever saw an envelope, but if Carsethorn's in the station, we'll soon find out. He was on that case with Thropton,” replied the Colonel, picking up the house-telephone.
“He is, sir,” said the Inspector. “I've just been having a word with him.”
The Sergeant came quickly in answer to the summons. Upon the question being put to him, his eyes narrowed, as though he were bringing a distant view into focus. After a moment's exercise of memory, he said positively: “No, sir. We never saw the envelope. Mr. Plenmeller handed the letter to Inspector Thropton, spread open, like it is now. He said something about supposing he'd got to give it to the police, though his instinct—no, his baser self was what he said—made him a sight more inclined to put it on the fire.”