He left the rest of you in this same gallery of the broken column, went straight out, strolled about the woods for half an hour or so and then returned to the hotel.

I fancy 'strolled' is not precisely the right word, but at any rate it's the word he uses.

Now that half hour in the woods is an unfortunate circumstance.

Had he gone directly to the hotel from the cave, we could have proved an alibi without any difficulty.

As it is, he had plenty of time after the others came out to remember that he had forgotten the coat, return for it, renew the quarrel with his father, and after the fatal result make his way to the hotel while the rest of the party were still loitering in the woods." "Terry--" I began.
He waved his hand in a gesture of dissent.
"Oh, I'm not saying that's what _did_ happen.