The coroner lost his head for a moment.
"How do you know it was locked?"
"Because I saw it. I got as far as his room, and I could have got him out if I could have got in. But it was locked, and it was too strong to break down. I went back to get an axe, but the floor of the corridor caved in before I could get back."
"Well, supposing his door was locked — what of it?" demanded the coroner in an exasperated voice. "Why shouldn't he lock his door?"
Simon spoke very gently and evenly.
"I imagine he had every reason for locking it," he replied. "When a man goes to stay in a house full of his bitterest enemies, people whom he's fighting with all the resources at his command, people to whom wholesale slaughter is merely a matter of business, he's a fool if he doesn't lock his door. But it hasn't been proved that he did lock it. I simply said that his door was locked; and I might add that the key was not in it."
"Beg pardon, sir." The captain of the fire brigade stood up at the far end of the room. "I found a door key among the daybree in the libry."
There was a hushed pause.
"Exactly," said the coroner, with sarcastic emphasis. "Kennet locked his door and took out the key. I fail to see any sinister implications in that — in fact, I have frequently done it myself."
"And have you frequently held inquests without bringing any evidence to establish the cause of death?" retorted the Saint recklessly.