The Black Echo

tunnels over there. But nothing that would have made me start looking at tunnel rats in particular. What was the lead to Meadows, people like me?”
    “First off, there was the C- 4,” she said. “Alcohol, Tobacco, and Firearms sent a team out to go through the concrete and steel from the blast hole. There were trace elements of the explosive. The ATF guys ran some tests and came up with C-4. I’m sure you know it. It was used in Vietnam. Tunnel rats used it especially to implode tunnels. The thing is, you can get much better stuff now, with more compressed impact area, easier handling and detonation. It’s even cheaper. Also less dangerous to handle and easier to get ahold of. So we figured-I mean the ATF lab guy figured-the reason C-4 was used was because the user was comfortable with it, had used it before. So right off we thought it would be a Vietnam-era vet.
    “Another corollary to Vietnam was the booby traps. We think that before they went up into the vault to start drilling, they wired the tunnel to protect their rear. We sent an ATF dog through as a precaution, you know, to make sure there wasn’t any more live C-4 lying around. The animal got a reading-indicated explosives-in two places in the tunnel. The midway point and at the entrance cut in the wall of the storm line. But there was nothing there anymore. The perps took it with them. But we found peg holes in the floor of the tunnel and snippets of steel wire at both spots-like the leftover stuff when you are cutting lengths with a wire cutter.”
    “Tripwires,” Bosch said.
    “Right. We’re thinking they had the tunnel wired for intruders. If anybody had come in from behind to take them, the tunnel would have gone up. They’d’ve been buried under Hill Street. At least, the tunnelers took the explosives out with them when they left. Saved us stumbling across them.”
    “But an explosion like that probably would’ve killed the tunnelers along with the intruders,” Bosch said.
    “We know. These guys just weren’t taking chances. They were heavily armed, fortified and ready to go down. Succeed or suicide…
    “Anyway, we didn’t narrow it down specifically to tunnel rats possibly being involved until somebody caught something when we were going over the tire tracks in the main sewer line. The tracks were here and there, no complete trail. So it took us a couple days to track them from the tunnel back to the entrance at the river wash. It wasn’t a straight shot. It’s a labyrinth down there. You had to know your way. We figured these guys weren’t sitting there on their ATVs with a flashlight and a map every night.”
    “Hansel and Gretel? They left crumbs along the way?”
    “Sort of. The walls down there have a lot of paint on them. You know, DWP marks, so they know where they are, what line is going where, dates of inspection and so forth. With all the paint on them, some look like the side of a 7-Eleven in an East L.A. barrio. So we figured the perps marked the way. We walked the trail and looked for reoccurring marks. There was only one. Kind of a peace sign, without the circle. Just three quick slash marks.”
    He knew the mark. He’d used it himself in tunnels twenty years ago. Three quick slashes on a tunnel wall with a knife. It was the symbol they’d used to mark their way, so they could find the way out again.
    Wish said, “One of the cops there that day-this was before LAPD turned the whole thing over to us-one of the robbery guys said he recognized it from Vietnam. He wasn’t a tunnel rat. But he told us about them. That’s how we connected it. From there, we went to the Department of Defense and the VA and got names. We got Meadows’s. We got yours. Others.”
    “How many others?”
    She pushed a six-inch stack of manila files across her desk.
    “They’re all here. Have a look if you want.”
    Rourke walked up then.
    “Agent Wish has told me about the letter you requested,” he said. “I have no problem with it. I roughed out something and we’ll try to get Senior Special Agent Whitcomb to sign it sometime today.”
    When Bosch didn’t say anything Rourke went on.
    “We may have overreacted yesterday, but I hope I’ve set everything straight with your lieutenant and your Internal Affairs people.” He gave a smile a politician would envy. “And by the way, I wanted to tell you I admire your record. Your military record. Myself, I served three tours. But I never went down into any of those ghastly