Christine had not the faintest idea, and said so. She could not add that the Chief Inspector had told her to consult Mr. Watts should any emergency arise while he was away.
Mrs. Erskine sank back into her chair. “He bade me 'phone to the Préfecture if anything unexpected should happen, and it's aye the unexpected to that man that happens in all his cases, I'm thinking. Well, instead of the Préfecture, I am going, as I told you, to employ a most clever French detective of whose skill I've had some verra good proofs indeed in other days. Now, Christine, my dear”—she had never called the girl that before—“just send a wire, or a letter, to your pension in Cannes and bide the night here with me. I have much to do. I need you. Leave me to myself now, but come you back at seven without fail and we will see what my Frenchman can do to clear up this dreadful discovery of yours.” Mrs. Erskine was deeply moved. She folded one trembling hand over the other, as though to keep them quiet by force.
“I canna believe it”—she turned her glowing eyes on the girl—“I canna yet believe what you've told me. To-night you must let me hear anything that you remember from my Rob's letters. The letters that I never received.”
Mrs. Erskine covered her face with her hands, and only made a gesture of farewell as Christine passed her.
“Don't fail me!” she breathed, and the girl laid a tender hand for a second on the bowed shoulder.
She herself spent the interval as in a dream. What did it mean? What could it mean? Was there really someone in the house with Mrs. Erskine who had substituted those brutal begging letters; but how had they been able to profit by the money? Surely there could not have been an accomplice at the other end as well? Someone who could take Mrs. Erskine's letters with their money contents and change them again for the cold, formal epistles which alone had reached Rob? Yet he had been allowed to receive the thousand pounds! Christine felt her head in a whirl, and she tried to think of something else as she walked by the sea. There was something, too, in Mrs. Erskine's manner which suggested that she knew more than she would admit. She was afraid of something, or someone. What or who? Christine was thankful that the mother could turn to an expert who could throw daylight on what seemed so dark, and to whom the other would at last speak out.
It was not quite seven when she returned to the villa.
It was on the afternoon of the same day that Pointer set out for Nice. He 'phoned to Christine from Marseilles, where the train had a wait. The puzzle had yielded to the key. He knew now the truth about Robert Erskine's murder, but he wanted her help with regard to his letters to his mother.
The Chief Inspector was told that mademoiselle was out, but would be back in the afternoon. A 'phone to the Negresco informed him that Crane was away too. He wondered if he had struck the weekly meeting day of the young couple, and left a message for Christine to expect a 'phone from Nice at the hour when his train arrived. A few words over the instrument would tell him all that he wanted to know. To “Colonel Hunter” he wired instructions to meet Mr. Deane at the station.