Free The Desert Thieves by Franklin W. Dixon

asked.
    â€œHe’s investigating possible medicinal properties in cacti such as the organ pipe,” she said.
    â€œIs he always so hard to get along with?” Joe asked.
    Diane bristled. “He works very hard, that’s all,”she said. “So do I. I’m a freshman at the university, and this is how I’m paying my expenses. I’ve been working as his assistant since last year, when I graduated from high school.”
    â€œWhy did he get so mad when we found that piece of cactus under his truck?” Joe asked.
    â€œI’m not sure,” she said. “Maybe because in his line of work he can’t afford to get a reputation for being careless about protecting the desert.”
    â€œThat makes sense,” Joe said.
    As they walked around some tall bushes, the two vehicles came into view. Perez was standing exactly where he’d been before, only now he was wearing a broad smile and was nearly trembling with excitement.
    â€œWhat’s up, Perez?” Joe asked.
    Perez’s grin grew wider. “Just glad to see you guys, that’s all,” he said. After greeting Diane, he said to the Hardys, “I’m ready to head back if you are.”
    â€œWhy the sudden hurry?” Joe asked.
    â€œNo reason, especially.” As Perez spoke, he glanced significantly at Diane, as if he was trying to tell Joe something.
    Joe opened the driver’s door of the car. “Tell your father thanks,” he said to Diane, “and we’ll bring back the tape tonight.”
    Diane slid her pack off and opened the door of the pickup. “I’ll tell him,” she said. “See you there.”
    Frank and Perez got into the car. As Joe started itup, Perez said, “I want you guys to look on the other side of the road, by that clump of dead grass. Don’t let Diane see you looking. What do you see?”
    â€œA pile of rocks,” Joe said. The pile was four stones high, made with flat rocks stacked one on top of the other. “That’s a common way for hikers to mark a trail. What about it?”
    â€œDo you see any hikers around here?” Perez asked.
    â€œWhat about it? What are you saying, Perez?”
    â€œI’m saying that you’re right,” Perez said. “That’s a marker. But you know what? I saw a marker like that at that first place we looked at this morning, the one I found for you.”
    Frank exchanged glances with Joe. This could be important, he thought. “So you think that marker might show where the thieves are going to hit next?” he asked.
    â€œMaybe not where they’ll hit next,” Perez said, “but probably where they’ll hit soon.” He elbowed Joe lightly in the arm and said, “And you said I don’t notice things, Joe. I’ll bet you missed that marker this morning, didn’t you?”
    Joe nodded. “I did,” he said flatly, pulling the car onto the road. As they passed the professor’s pickup, Diane looked back and waved.
    â€œThere’s more,” Perez said. “While you guys were out walking, I took a good look in Professor Townsend’s truck. Know what I found? A winch! A big one. A winch big enough to handle a good-size cactus.”
    â€œI didn’t see a winch when we got a ride with him before,” Frank said.
    â€œThat’s because it’s anchored at the front of the truck bed, not the back,” Perez said, “and it has a cardboard box over it. Looks like a box of parts or tools. The winch is heavy-duty, with steel cable. If he ran the cable up and over a high frame, it could lift a pretty big cactus right out of the ground. Not a giant cactus, but certainly a small- to medium-size one.” Perez folded his arms across his chest. “Personally, I think I just solved the case.”
    Neither of the Hardys said anything. They both knew Perez hadn’t solved the case. If they assumed he wasn’t one of the