"I'm afraid I couldn't. It was in the evening, and I was sitting by the window, studying. I happened to look up and I saw this fellow moving about under the trees near the wall. Later on I heard one of the dogs barking in another part of the grounds, and shortly afterward I saw some one running across the lawn. But I thought it was probably just a tramp." "Did he wear a hat or a cap?" "As near as I can remember, it was a cap. His clothes were dark." "And you couldn't see his face?" "No." "Well, it's not much to go on, but it might be linked up with Frank's idea that the man who stole the roadster might have still been hanging around." Mr. Hardy thought deeply for a few moments. "I am going to bring all these facts to Mr. Applegate's attention and I am also going to have a talk with the police authorities. I don't think they have enough evidence to warrant holding your father, Perry." "Do you think you can have him released?" asked the boy eagerly. "I'm sure of it. In fact, I think Mr. Applegate is beginning to realize now that he made a mistake and I don't think the police are any too anxious to go ahead with the case on the meager evidence in their possession." "It will be wonderful if we can have dad back with us again," said Perry. "Although it won't be quite the same. He'll be under a cloud as long as this mystery isn't cleared up. And of course Mr. Applegate won't employ him any more." "All the more reason why we should get busy and clear up the affair," returned Mr. Hardy. "You boys can help." "How?" "By keeping your eyes and ears open and by using your wits. That's all there is to detective work." "Well, you can just bet that if it will clear Slim's dad we'll be listening and looking for every clue there is," Joe assured his father. CHAPTER X AN IMPORTANT DISCOVERY When the Hardy boys returned from school next afternoon they saw that a crowd had collected about the bulletin board in the post office. "Wonder what's up now?" said Joe, pushing his way forward. Boylike, he was able to make his way through the crowd with the agility of an eel, and Frank was not slow in following. On the board was a large poster, the ink on which was scarcely dry. At the top, in enormous black letters, they read: $1000 REWARD Underneath, in slightly smaller type, came the following: The above reward will be paid for information leading to the arrest of the person or persons who broke into Tower Mansion and stole from a safe in the library jewels and securities, as follows-- Then came a list of the jewels and negotiable bonds that had been taken from Tower Mansion, the jewels being fully described and the numbers of the bonds being given. It was announced that the reward was offered by Hurd Applegate. "Why, that must mean that the charge against Mr. Robinson has been dropped!" exclaimed Joe. "It looks like it. Let's go and see if we can't find Slim."