“I not understand,” said the boy politely.
Mr. Goon appeared to think the boy was deaf. So he raised his voice and shouted. “I said - what you waiting for?”
“I wait for a - what you say? - answer. Ah, yes, I wait for the answer,” said the boy.
“H’m!” said Mr. Goon, and slit the envelope open. He unfolded the blank sheet and stared at it. His face went purple.
“See here!” said Mr. Goon, and he thrust the blank letter in the boy’s face. “Some one’s been playing a joke on me - silly sort of joke, too - wasting the time of the Law like this. Who gave you the letter?”
“I not understand,” said the boy, and smiled politely at the policeman, showing all his jutting-out teeth. “It is a mystery, is it not? A letter with nothing in it. Ah, truly a great mystery!”
The word “mystery” seemed to strike Mr. Goon. Since the children had solved two strange mysteries before he did, he had been rather sensitive about mysteries, and terribly afraid that the children might happen on a third one before he did. He gazed at the letter.
“Maybe it’s a secret letter,” he said. “Maybe it’s got a secret message. Who gave this to you, boy?”
“I not understand,” said the boy irritatingly.
“Well - I’ll test the paper for secret ink,” said Mr. Goon most surprisingly.