“By the way, how did you boys get in the school?” asked Professor Long, suddenly.

“I—er—we—that is——”

“Never mind,” hastily interrupted the instructor, “I should not have asked that. I have no wish to pry further into this matter than is necessary. Believe me, I appreciate your motive in making a clean breast of it. I do not care to know all the details. Boys will be boys, I suppose. Only get me back the diamond bracelet and the turtle. I will see Mr. McCloud at once, and I’m sure he will let you make a search at Fenn’s house.”

Bart’s opportunity had passed. If he only had mentioned the fact that he and his chums found the front door open, and had seen a mysterious man enter the school, things might have turned out differently, and much trouble have been averted. But now it was too late. Mr. Long hurried to the office of the principal, and returned shortly with permission for the four chums to go and make a search.

“But why didn’t you tell him about the man we saw?” asked Ned, as they were on their way to Fenn’s house.

“Because,” answered Bart.

“That’s a regular girl’s reason,” objected Frank.

“Well,” answered Bart desperately, somewhat weary and nervous over the ordeal through which he had gone, “the chief reason was that if I told that, I’d have to tell why we didn’t notify the police. That’s where we made a mistake. If that fellow was a thief, and took the bracelet, we should have called the police.”

“We didn’t know he was a thief—we don’t know it yet,” declared Frank.