"What took you to Hyde Park on this night?"
"Mrs. Pentreddle asked me to go on an errand for her."
"What was the errand?"
"What indeed?" said Mrs. Sellars curiously. "Martha, poor dear, was always of a very secretive disposition, and never told me anything. But, as I am her own sister, she ought to have told me what she wanted."
Patricia took no notice of this remark, but addressed herself to Inspector Harkness. She wished to get the interview over, so that she could retire to bed, for she felt extremely tired, and only her will-power enabled her to sustain the examination. "Mrs. Pentreddle," she explained, and the officer took down her words, "had an appointment to-night with a man near the Serpentine Bridge on this side. Owing to her sprained ankle she could not go herself, so she promised me five pounds if I would go in place of her. At first I objected, since the conditions under which I was to meet this man were so strange; but when Mrs. Pentreddle declared that, failing me, she would ring up a messenger-boy on the telephone, I thought that there could be nothing wrong, and accepted the commission."
"For the sake of the five pounds," hinted the inspector.
Patricia threw back her head proudly. "I am not rich, and five pounds mean much to me," she said simply, but with a nervous flush. "Yes, I went for the sake of the five pounds. Though, of course," she added quietly, "I was quite willing to oblige Mrs. Pentreddle in every way. I refused the money at first, but when she insisted upon paying me, I was only too delighted to accept. Do you blame me?"
"Well, no," acknowledged the officer, after a pause. "But did you not think that five pounds was a rather large sum to pay for a simple errand?"
"And Martha was so close-fisted as a rule," put in Mr. Sellars.
"The errand was not a simple one," said Patricia quickly. "There was a very great deal of mystery about it," and she repeated the instructions which the dead woman had given her. These both impressed the inspector and startled Mrs. Sellars.