“An aeroplane on the roof!” murmured the officer, as if unable to believe it. “Do you think, Jerry——”
“I think,” interrupted the tall lad, “that the bank burglars came through the air, made a landing here unseen by anyone in the street, went down the scuttle, looted the safe, and made a flying start from this roof.”
“Wait! Wait!” begged Mr. Thompson. “This is a new theory—I never heard the like before. It needs a regular detective to consider this. Wait until I get Blake up here. I’ll wager it’ll be news to him. Wait here for me.”
He hurried down the scuttle, and the boys eagerly looked for more impressions and talked about Jerry’s discovery. They went to the end of the row of buildings, and there, where the roof was of tar and gravel, they found in the soft black material the plain impression of the three wheels. They came to a sudden stop before “the jumping-off place,” as Jerry called it, was reached.
“Here’s where they sailed into the air,” he declared confidently.
“Let’s see if we can find where they landed,” suggested Ned.
They did, at the opposite end of the row of roofs, just where a tall building reared itself several stories higher than the row of low structures.
“They came down here all right,” declared Jerry excitedly pointing to the deep impression made by the wheels. The boys even found the place where the drag-brake had scraped a long line in the gravel, and that, to them, made their “case complete.”
Suddenly the merchant’s son uttered a cry, and straightened up.
“What’s the matter?” asked Jerry in surprise.