“None at all, Dad, unless the person who stole them from me left them at the airport.”
“And you, Joe? How about the footprints?”
“All I can say is that somebody else must have a pair of shoes like mine. Neither Frank nor I ever went near the airport.”
“I think,” said Fenton Hardy, “it wouldn’t be a bad idea if we went out to the airport now. We’ll have to look over the ground.”
XIV
Held for Trial
Chief Collig accompanied Fenton Hardy and the two boys out to the airport, taking them there in his own car. The road entering the grounds was under guard, and the big hangars were closely watched, the authorities evidently taking no chances on a repetition of the robbery. However, Chief Collig was readily admitted and the party proceeded to a hangar where a newspaper photographer was busy taking pictures.
“I’d like to see those footprints, Chief, if you don’t mind,” said Mr. Hardy.
“They haven’t been touched,” said Chief Collig. “I gave strict orders they weren’t to be disturbed.”
Close by the hangar wall a few boards covered the ground. The chief raised them, and in the ground beneath they could see the clear imprint of a foot. The marks of the rubber sole were identical with those made by Joe’s shoes.
“Let’s see how your foot fits that,” suggested the chief, turning to Joe.
Without hesitation, Joe stepped forward. He placed his right foot in the print. It fitted exactly. When he removed his foot there had been not the slightest change in the original print in the ground.
“Yet you said you were never here before!” exclaimed the chief.
“I still say it,” Joe insisted.
“Then how do you account for that footprint? Same size, same marks, same everything.”
“Somebody must have had a shoe just like mine. That’s all I can say.”
The chief sniffed dubiously. Then Fenton Hardy, who had been examining the footprint, made a suggestion.
“Joe,” he said, “I want you to stand in the earth right beside that other footprint. Just walk across there, stand for a moment, and move away.”
Wondering, Joe obeyed. When he had done as his father asked, there were several new footprints in the soft earth. Mr. Hardy looked at them closely.
“What do you think of that, Chief?” he asked.
Chief Collig looked down at the footprints.
“Not much difference, so far as I can see,” he grunted.
“Not much. But there is a difference, isn’t there?”
“The footprints Joe just made don’t seem as heavy as the other one,” admitted the chief.
“They certainly aren’t. You can see how light the impressions are in the earth. That first footprint is pressed down quite heavily. You couldn’t help but see it, and I think it was meant to be seen. Joe’s natural footprints, on the other hand, are scarcely visible.”
“What of it?” demanded the chief.
“I mean,” said Fenton Hardy, “that the footprint you found here is not Joe’s natural footprint at all. It’s all very well to say that the size and the sole markings are identical, but there is more to a footprint than that. The first footprint was made by a very heavy person, as you can see by comparing it with the footprints Joe made just now.” He turned to his son. “How much do you weigh, Joe?”
“One hundred and twenty-five pounds,” Joe answered promptly.
“That’s not very heavy. But that first footprint was certainly made by a person weighing considerably more than that. The earth here is no harder now than it was at the time of the robbery, because it has been covered over by the boards, so I think the test proves itself. Then, to go further, wasn’t there another footprint, Chief? You have shown us only one, the conclusion being that the thief was a one-legged man.”
“There’s another footprint,” declared Collig. “Here it is.” He pointed to an impression in the earth a short distance away.
Fenton Hardy took a small folding measuring rule from his pocket and measured the distance between the two original prints. Then he measured Joe’s footprints.
“More proof,” he said finally. “The distance between these first two prints is a good seven inches more than the distance between Joe’s actual footprints. That proves that the man who wore those shoes was a good deal taller than Joe, with a longer stride. It also proves that when he made that heavy print in the mud he was not simply standing still, which might have caused the print to be heavier by reason of his weight. Otherwise his feet would have been close together. He was walking, just as Joe was walking a moment ago.”
Chief Collig was puzzled. Fenton Hardy’s deductions came as a rude shock, for the chief had already made up his mind that the Hardy boys were guilty and the evidence had seemed conclusive to him. He was not a man who admitted a mistake readily and he clung obstinately to his original belief.
“I don’t care how you figure it out,” he said roughly. “Your boys can’t explain how that sweater and the knife got here. And they can’t prove an alibi. I’m not going to let them go just because one footprint is a little bit heavier than the other.”
“You mean we’re still under arrest?” asked Frank anxiously.
The chief nodded. “You’re under arrest,” he said. “We’d better be starting back to the city.”
Fenton Hardy patted Frank’s shoulder.
“Never mind, Son,” he said. “I’m afraid I can’t convince Chief Collig just now, but at any rate I’m sure of your innocence. And we’ll prove it yet.”
There was nothing more the detective could do. They left the airport and got back into the chief’s car. Gloomily, they drove back to the city.
That afternoon, Frank and Joe Hardy were arraigned before a magistrate and, after the evidence had been presented, they were held for trial on the serious charge of robbing the air mail.
“Held for the
