"What are you staring at, Sammy?" asked George.
"He looks like a cat watching at a mousehole," remarked Bob.
"I bet he's working up another mystery," mocked Frank. "I know the signs."
"Never you mind," said Sammy, impressively. "I know exactly what I'm doing."
"That's something new for Sammy, then," gibed Frank. "Most of the time he thinks he knows but he doesn't."
"What would you say," said Sammy, stung out of his resolve to keep the matter quiet for the present, "if I told you that in this same car where you're eating there are two murderers?"
This came to the boys like an electrical shock.
"What do you mean?" asked Frank.
"Stop trying to fool us," said Bob.
"Is that a joke?" demanded George.