Suddenly Casco jumped to his feet.
“I forgot to ask Cabot about something,” he cried. “Just wait till I come back.”
He made for the door. Bob tried to retreat, but he was too late. Out in the hall Casco overtook him, and caught him by the shoulder.
“Who are you?” he demanded.
“Let me go!” cried Bob.
He tried to break away, but the scar-faced man held him fast.
“Hullo, it’s that Bob Alden! How did you get in here?”
“Walked in. Let me go!”
“Oh, I’ll let you go!” returned Casco, sarcastically. “Hi, there, boys, here’s a spy!”
“Sure, an’ who is it?”