"Is it important to the case?" asked Glass.
"Of course it's important. I don't say it makes it any easier, because it doesn't, but that's what I told you: in cases like this you're always coming up against new bits of evidence which go and upset any theory you may have been working on. On the face of it, it looks as though the man you saw - we'll assume it was Carpenter - did the murder, doesn't it?"
"That is so," agreed Glass.
"Well, the fact of that hall clock's being a minute slow throws a spanner in the works," said the Sergeant. "In the second act of her highly talented performance, Mrs. North stated that that clock struck the hour, which was 10 p.m., while she was in the hall, on her way to the front door. You saw Carpenter making his getaway at 10.02. That gave him a couple of minutes in which to have killed the late Ernie, disposed of the weapon, and reached the gate. It's my opinion it couldn't have been done, but at least there was an outside chance. Now I discover that when Mrs. North left the study it wasn't 10.00, but 10.01, and that's properly upset things. It begins to look as though Carpenter wasn't in on the murder at all, but simply went down to try his luck at putting the black on the late Ernie, and was shown off the premises as described by Mrs. North. In fact, it wouldn't surprise me if Carpenter turns out to be one of those highly irrelevant things that seem to crop up just to make life harder. The real murderer must have been hiding in the garden, waiting for his opportunity, and while you were taking notice of Carpenter, and deciding to go and investigate, he was doing the job." ~
Glass considered this for a moment. "It is possible, but how did he make his escape? I saw no one in the garden."
"I daresay you didn't see anyone, but you didn't go looking behind every bush, did you? You flashed your torch round, and thought there was no one in the garden. There might have been, and what was to stop him making his getaway while you were in the study?"
They had reached the police station by this time. Glass paused on the steps, and said slowly: "It does not seem to me that it can have happened like that. I do not say it was impossible, but you would have me believe that between 10.01, when Mrs. North left the house, and 10.05, when I discovered the body, a man had time to come forth from his hiding-place, enter the study, slay Ernest Fletcher, and return to his hiding-place. It is true that I myself did not enter the study until 10.05, but as I came up the path must I not have seen a man escaping thence?"
"You know, when you keep your mind on the job you're not so dumb," said the Sergeant encouragingly. "All the same, I've got an answer to that one. Who says the murderer escaped by way of the side gate? What was to stop him letting himself out the same way Mrs. North did - by the front door?"
Glass looked incredulous. "He must be a madman who would do so! Would he run the risk of being seen by a member of the household, perhaps by Mrs. North, who had only a minute or two before passed through the study door into the hall, as he must have known, had he been lying in wait as you suggest?"
"Heard you coming up the path, and had to take a chance," said the Sergeant.