“But, had it been forced, such marks would inevitably be seen?”
“Yes.”
“Then it was not forced?”
“Of course not. However, it was not my idea that it had been entered that way. I took it that they might have found the key on Mr. Field and helped themselves.”
The detective quietly said:
“They were not even in this room, so they could not well have opened the safe.”
“How can you know that?”
“Easy enough. The feet of the persons were muddy, as was shown by the marks and dirt left upon the carpet of the rooms upstairs. In this room is no trace of anything of the kind.”
Barnes exclaimed:
“Now that you bring it to mind, it is as clear as day! Do you know one thing?”