“Because it wasn’t her shovel. Mason gave it to Billy to take to Blackwater Landing—after wiping his own prints off it, of course. I asked Mary Beth about it. She said that Billy came out of the bushes carrying it. Mason figured it would be the perfect murder weapon—because as an archaeologist Mary Beth’d probably have a shovel with her. Well, Billy gets to Blackwater Landing and sees Garrett with her. He figures he’ll kill the Insect Boy too. But Garrett got the shovel away and hit Billy. He thought he killed him. But he didn’t.”

“Garrett didn’t kill Billy?”

“No, no, no…. He only hit Billy once or twice. Knocked him out but didn’t hurt him that seriously. Then Garrett took Mary Beth away with him to the moonshiners’ cabin. Mason was the first on the scene. He admitted that.”

“That’s right. He took the call.”

“Kind of a coincidence that he was nearby, don’t you think?” Rhyme asked.

“I guess. I didn’t think about it at the time.”

“Mason found Billy. He picked up the shovel—wearing latex evidence gloves—and beat the boy until he died.”

“How do you know that?”

“Because of the position of the latex prints. I had Ben reexamine the handle of the shovel an hour ago with an alternative light source. Mason held the shovel like a baseball bat. That’s not how somebody would pick up evidence at a crime scene. And he adjusted his grip a number of times to get better leverage. When Sachs was at the crime scene she said the blood pattern showed Billy’d been hit first in the head and knocked down. But he was still alive. Until Mason hit him in the neck with the shovel.”

Bell looked out the window, his face hollow. “Why would Mason kill Billy?”

“He probably figured that Billy’d panic and tell the truth. Or maybe the boy was conscious when Mason got there and said he was fed up and wanted out of the deal.”

“So that’s why you wanted Mason to leave … a few minutes ago. I wondered what that was about. So how’re we going to prove all of this, Lincoln?”