"Then this third person may be the one who opened the safe."
"That is the theory of the defense," Will explained.
"But what's all this got to do with the mark of a man's right thumb?" asked George.
"I'm coming to that," Will went on. "The three men who were in the office that night—we are supposing for the sake of the argument that there were three men there, and that the man who says he wasn't there is lying about it—were looking over a set of plans for a new machine which the company was arranging to manufacture."
"I've got you now!" laughed Sandy. "The thumb print of the third man was left on the drawings!"
"That's the idea," admitted Will. "The two men say that they were not a little annoyed during the course of the evening because this man, Babcock, persisted in pawing over the plans with dirty hands. They declare that the marks of both thumbs are to be seen on drawings, not in plain dust and grime, but in ink."
"He must have spilled the ink," suggested George.
"That's what they say," Will replied.
"Well, go on!" urged George.
"The statement is made by the two accused men that they worked over the plans until after midnight, and that they left this man Babcock at the office when they went to their homes. Babcock denied that he was in the office at all that night."