“For the reason why the door stuck,” said Bob tartly. Then he found it—a thin sliver of steel that had been inserted as a wedge. It was an innocent enough looking piece, but when placed properly in a door could cause considerable delay.
Bob picked it up and placed it in his pocket. Although he was not aware of it at the time, it was the first piece of evidence in a mystery which was to pull him deep into its folds and require weeks of patient effort to untangle.
The guard had edged over to the door and now reached out to pull it shut. Only a sharp order from Bob stopped him.
“Keep your hands off the doorknob,” he ordered. “Someone was tampering here and I don’t want you messing your hands around the place.”
The guard hesitated as though undecided whether to obey Bob, and the clerk stood up and doubled up a fist.
“Better not touch that door.” There was a steelly quietness in the words that decided the guard, and he stepped well back into the corridor.
“You’d better get back to your post. I’ll take care of this situation,” said Bob. “I’ll keep your flashlight and return it to you when I leave the building. I want to do a little scouting around and may need this light.”
The guard grumbled something under his breath, but retreated down the corridor and finally vanished from sight. Bob disliked him thoroughly for his attitude had been one of sullen defiance; so unusual from the men generally on duty at night. It might be well to speak to Jacobs about it in the morning.
Just to make sure that no one came along and touched the doorknob, Bob took out his handkerchief and tied it around the knob in a manner which would protect possible fingerprints.
That done, he picked up the flashlight again and started to reconnoiter in the corridor, trying one door after another. There was just a possibility that the marauder had found a hiding place in an office which had been left unlocked. Bob knew that it was almost a useless quest, for the offices were checked each night.