“You mean you’d give yourself a bit of a run for your money?”

“Yes, that’s what I mean. If you were going to do it deliberately, that is to say⁠—and lock yourself in before you began.”

Cayley had been silent, apparently thinking over this new idea. With his eyes still on the ground, he said now: “I hold to my opinion that it was purely accidental, and that Mark lost his head and ran away.”

“But what about the key?” asked Bill.

“We don’t know yet that the keys were outside. I don’t at all agree with Mr. Gillingham that the keys of the downstairs rooms are always outside the doors. Sometimes they are, no doubt; but I think we shall probably find that these are inside.”