"I see, he might have proved an alibi."

"Exactly, my dear Watson; he might have proved an alibi. We will
suppose, for argument's sake, that the household of Wisteria
Lodge are confederates in some design. The attempt, whatever it
may be, is to come off, we will say, before one o'clock. By some
juggling of the clocks it is quite possible that they may have
got Scott Eccles to bed earlier than he thought, but in any case
it is likely that when Garcia went out of his way to tell him
that it was one it was really not more than twelve. If Garcia
could do whatever he had to do and be back by the hour mentioned
he had evidently a powerful reply to any accusation. Here was
this irreproachable Englishman ready to swear in any court of law
that the accused was in the house all the time. It was an
insurance against the worst."

"Yes, yes, I see that. But how about the disappearance of the
others?"

"I have not all my facts yet, but I do not think there are any
insuperable difficulties. Still, it is an error to argue in
front of your data. You find yourself insensibly twisting them
round to fit your theories."

"And the message?"

"How did it run? 'Our own colours, green and white.' Sounds
like racing. 'Green open, white shut.' That is clearly a
signal. 'Main stair, first corridor, seventh right, green