“I remember now,” she said after a pause. “I went out to the post office that afternoon.”

“Was anybody with you?”

“No, but Mrs. Holt at the post office will remember, because Gandhi chased—I mean, her cat ran after Gandhi, all over the shop. There was quite a fuss about it.”

The sergeant laughed.

“Excellent!” he said. “I will see Mrs. Holt on my way back. Now there is only one more date—the worst case of all. Friday the 20th, that is, yesterday, some time in the morning.”

“I know that can’t have been Gandhi,” said Susan triumphantly. “I was out riding on the downs that day, and he was with me all the time.”

“Are you sure it was Friday morning?”

“Certain. I had been dancing in Brighton the night before.”

“How does that help you to remember it?”

“Because the—the person I had been dancing with stayed the night here and we went riding together the next day.”

Susan was enraged to feel herself blushing like an early nineteenth-century miss as she made the reply. It may be that the sergeant noticed it, for his next question was: “Is he an independent witness?”

“Not independent exactly,” answered Susan, as coolly as she could. “As a matter of fact, we’re engaged to be married. If you want his name and address,” she went on, “here it is.” And she handed him the letter which she had addressed that morning.

“Thank you, miss,” said the sergeant. He copied the address in his notebook, and handed back the letter. “May I be allowed to congratulate you?” he added, with grave courtesy.

“Thank you,” said Susan in some confusion. First congratulations are sweet, even when they come from a police officer.

Meanwhile the sergeant had risen to his feet.

“Will the wedding be soon?” he asked.

“Oh, quite soon. We’ve waited long enough as it is.”

“Just so. And you’ll be living in the country, no doubt?”

“No. We’ve just had the offer of a share in a farm in Kenya. We shall go out there as soon as we’re married.”

“Ah, Kenya,” said the sergeant musingly. “Well, I hope you’ll be very happy there. I’m sure. It’s a fine life, they tell me, for those that have a bit of capital behind them.”

“Yes, it’s a wonderful chance, isn’t it?” said the girl eagerly. “It’s what I’ve always wanted, but I never thought we could manage it. I was so surprised when he told me——” She stopped abruptly, as though she had only just realized how far the conversation had led her away from the matter in hand into her private affairs. “Is there anything else I can tell you, sergeant?” she went on in a different tone.