“It’s got two wheels and it can be towed on the back of a pickup,” Bosch said. “I’ve got a picture here somewhere I can show you. The point is, the grave wasn’t dug with a shovel. It was too precise, and it was clear that some solid rock had been split by something with more force than a shovel or a pickax. The grave was close enough to the paved road up there that he could have backed in there with the excavator and used it to get in and out pretty quickly. And one of the first machines McShane sold after the family disappeared was an excavator. We can prove that.”

Bosch pulled open one of the murder books on his desk and started leafing through it, looking for the photo of the excavator. He spoke as he searched.

“We were able to trace that sale, and the buyer let us examine the excavator. There was still a piece of rock lodged in one of the tire treads that matched the creosote at the gravesite.”

“All four were in one grave?” Rawls asked.

“Yes,” Bosch said. “It would have been the fastest way to do it. The hole was about six by four and then four feet deep. The parents were dropped in first, then the children on top of them. Along with the nail gun.”

He found a brochure from Shamrock Industrial Rentals that showed the excavator in question. He handed it over the partition to Masser.

“But that was the only link we ever made to McShane, and it wasn’t enough for an arrest warrant,” Bosch said.

“You went to the D.A. with this?” Masser asked. “I would have been tempted to file.”

“I did, and I guess I wish I’d come to you,” Bosch said. “The filing deputy I brought it to said he wanted more. McShane selling the excavator was not proof he used it to bury the family. There were holes in the linkage. The equipment yard was unguarded at night. Someone could have used Stephen Gallagher’s keys to open the yard and take the excavator for the night.”

“That’s a hell of a stretch,” Masser said.

“I felt the same,” Bosch said. “But I didn’t get to make the call. I was told to get more evidence … and I didn’t. So plan B was to find McShane, stick him in a room, and get him to cop-out. But that never happened and he’s still in the wind. That’s where it stands.”

Finished with his summary, Bosch waited for more questions and suggestions from the others. There was only silence until finally Hatteras asked, “Do you still have the original letter McShane wrote expressing his innocence?” she asked.

“We do,” Bosch said. “It’s handwritten on letterhead from the company.”