“Something to do with that mysterious letter,” Hannasyde said instantly.
“Yes, everything. You see, I was present when Miss Vereker gave Violet Williams that letter to post. She gave it her on the night of Roger's death - after seven o'clock.” He paused, and looked at Hannasyde. “Which meant, of course, that having missed the six-thirty collection it would catch the next - I don't know the exact time, but I suppose not earlier than eight-thirty, and probably later. I have a great respect for the Post Office, but I can't bring myself to believe that a letter posted at that hour can possibly be delivered at its destination the same evening. Violet Williams must have used the letter as an excuse to call on Roger at that unconventional hour.”
“What hour?” Hannasyde asked. “Have you any idea?”
“Sometime after eleven - when the girl she had invited to spend the evening with her left - and certainly before twelve, when she knew the main door would be shut.”
“Yes, I see. Coinciding with the entrance of the woman who might have been Mrs Delaford's personal maid, and the noise which was thought to be a tyre burst, heard by Mr Muskett. Is there a possibility of her having delivered the letter by hand prior to the arrival of her visitor?”
“No, I think not. She told me that her visitor came to dinner with her, and I expect you'll find she was speaking the truth. She wouldn't have had time.”
There was a long silence. Then Hannasyde said ruefully: “If all this turns out to be true, you'll have made me look rather silly - Mr Holmes.”
“Not at all,” replied Giles. “I only got on to it because I'm on very intimate terms with my cousins, and have been in a position to watch every move in the game at close quarters, as you never could.”
“I ought to have thought of it,” Hannasyde said. “If it hadn't seemed so certain that she'd never met Arnold Vereker, I must have thought of it. She was the only other person who had a motive.”
Giles laughed. “I really don't think you can blame yourself! My young cousin has been building up far too damning a case against himself to admit of your looking beyond him for some really unlikely suspect. All the same, you've never felt sure that Kenneth did it, have you?”