Bob and Joe looked at each other. The spark machine!

“That proves it!” Bob whispered, gritting his teeth. “They’re the fellows that set your dad’s garage on fire, all right! We’ll make them——”

“Shhh!”

“But listen, Tim,” one of the men was saying, “there ain’t any use to get hot-headed yet. I know this guy pretty well. I’ve done a lot for him and he’s done a lot for me. He’s never backed out on me yet. He’s got plenty of money, even if he is tryin’ hard to get more.

“Here’s what let’s do. Let’s give him till tomorrow night, and then if he don’t pay us we can go after him.”

“All right.” And the agreement was made.

Bob and Joe looked at each other. What were they to do now? They had secured evidence that these men were the guilty ones. Now would it be best to report the matter to the police at once, or had they better wait longer for any further information that the crooks might unknowingly give them?

“Let’s wait a few more minutes,” suggested Joe. “They might leave the house just as we made for our car, and then it would be too bad.”

Bob thought this good advice, and he leaned against the house to wait. Joe remained at the window.

For a minute there was silence inside. Then the man called Tim got up from his chair and started for the door.