“Yes, he did that. By that time I was satisfied that the boy had been in on the robbery—that he had been forced to enter the building by way of a window and open the door for the thieves to enter.
“I knew that the boy would tell the whole story to me if I could get him away from the robbers, and not scare him half to death by putting him in jail. So I followed him along down the river. As the robbers were making their way down toward New Orleans, too, I was doing a pretty good job following him—and especially as the robbers were after him, too. They believed, all but Sam, he had taken the diamonds, you see.
“They got him last night and searched him, but found nothing. Then they told him that if he would get Alex. and Case into their hands they would let him go. So Chet did that very thing, and now the two boys are witnesses that the robbers admitted to them that they were in on the robbery!
“When they let Chet go he made for the Rambler on a run, and found me on the way. All the people who were in the old house are under arrest. And the diamonds are up at Memphis in the deposit vault, and all is well.”
“How do you know that?” demanded Clay.
“Why, we opened the box, the cashier and I,” was the reply. “I knew they were there before I knew that Chet had ever had them. My one great difficulty was to get hold of the boy after he ran off at Memphis! Your boat was watched all the way down, you know, of course.”
Then Clay told of his talk with the sheriff, and they all laughed at the idea that they had not seen through it all long before.
“If Chet had kept to boats I could have found him,” Red went on, “but he rode on wreckage, and that made it difficult. I might have saved you boys and Chet some of this mystery talk if I had told you about it when I had Alex. in the cabin of my boat, after I knew where the diamonds were, but I thought I would let it work out for itself, especially as I was having the time of my life.”
“I suppose those three mechanics were detectives, too?” asked Case.
“They were just what they represented themselves to be,” was the reply, “and they got good positions at Vicksburg. They are expecting to meet you down the river, in a houseboat of their own. I saw them soon after they left you.”