“I was there for all of it,” he said. “I remember it as if it happened today. Because it did.”

“Lassiter had no idea who Ellen Svaco was,” Shawn said.

“She never went to the police. She told us that story to manipulate us into helping her.”

“Why all this intrigue? She lost her necklace on a field trip.”

The car inched forward.

“I don’t think it was lost,” Shawn said. “I don’t think she’d ever had it. And I have a feeling if we asked at her school, we’d discover that the Descanso Gardens field trip was her idea. But it wasn’t really a field trip.”

“Then what was it?”

“A handoff,” Shawn said. “She brought the kids there as cover so she could collect the necklace.”

“From the tree?”

“From the lost and found,” Shawn said. “I’m sure someone turned it in a few days before.”

“Why so long?” Gus said. “And why the lost and found? Why not just give it to her?”

“Whoever had it must have been worried he was being followed,” Shawn said. “He couldn’t take a chance on meeting Ellen Svaco in person. And then something happened-maybe he caught a glimpse of whoever was following him. He panicked. He ran-but first he stopped by Descanso Gardens and turned the necklace in to the lost-and-found booth. Somehow he let her know it was there.”

“So why didn’t she just go pick it up?” Gus said as the car moved forward another couple of inches.

“She must have thought there was a chance she was being followed, too,” Shawn said. “If she was, it might seem suspicious for her to zip off to La Canada a day after her contact disappeared from around there.”

“That’s why you said the necklace had been there a couple of days.”

“You can’t just slap together a school field trip in an afternoon,” Shawn said. “And she needed the cover.”

“So she went to Descanso Gardens, but she didn’t pick up the locket.”

“Something made her suspicious,” Shawn said. “I’d guess it was having her other necklace stolen.”