I've been on many informant-led expeditions, and in a lot of cases the trip is a waste of time. Jailhouse tips are notoriously unreliable, either because the herald is lying, or because his memory has simply failed him. LaManche and I went twice in search of a septic tank reported to be the tomb of a murder victim. Two safaris, no tank. The snitch went back to jail, and the taxpayers picked up the bill.

Finally, Rinaldi returned to the Jeep.

"It's farther up."

"How much farther?"

"What am I, a geographer? Look, I'll know the spot when I see it. There was a wooden shed."

"You're repeating yourself, Frog." Claudel looked pointedly at his watch.

"Sacre b/eu! If you'll quit riding my ass and drive a bit farther you'll get your stiffs."

"You'd better be right, Frog. Or you will be at the center of the biggest cluster fuck of the millennium."

The men climbed back into the Jeep and the procession crept slowly forward. Within twenty yards Rinaldi held up his hands. Then he gripped the seat behind my shoulders and strained forward to peer through the windshield,

"Hold it."

Quickwater braked.

"There. That's it."

Rinaldi pointed to the roofless walls of a small wooden structure. Most of the shed had fallen in on itself, and fragments of roofing and rotten wood lay strewn around the ground.

Everyone got out. Rinaldi did a three-sixty, hesitated briefly, then set off into the woods at a forty-degree angle from the shed.

Claudel and I followed, picking our way through last year's vines and creepers, and slapping back branches still weeks from budding. The sun was well above the horizon now, and the trees threw long, spiderweb shadows across the soggy ground.

When we caught up to Rinaldi he was standing at the edge of a clearing, hands dangling in front, shoulders rounded like those of a male chimp about to put on a display. The look on his face was not reassuring.

"This place has changed, man. I don't remember so many trees. We used to come out here to light bonfires and get wasted."

"I don't care how you and your friends passed your summers, Frog. You're running out of time here. You're going to be doing twenty-five hard ones and we're all going to read about how they found you with a pipe up your ass on the shower room floor."

I'd never heard Claudel quite so colorful.

Rinaldi's jaw muscles bunched, but he said nothing. Though there had been frost that morning he wore only a black T-shirt and jeans. His arms looked thin and sinewy and goose bumps puckered the pale flesh.

He turned and walked to the middle of the clearing. On the right the land sloped gently to a small creek. Rinaldi cut through a stand of long-needle pines to the bank, looked in both directions, then headed upstream. Quickwater, Claudel, and I followed. Within twenty yards Rinaldi stopped and waved his scrawny arms at an expanse of bare earth. It lay between the stream and a mound of boulders, and was scattered with branches, plastic containers and cans, and the usual detritus thrown up by seasonal flooding.

"There's your fucking graves.

I looked at his face. It was composed now, the look of uncertainty once again replaced by cocky insolence.

"If that's all you're offering, Frog, that pipe has your name on it." Claudel.

"Don't fuck me over, man. It's been more than ten years. If the broad knows her shit, she'll find them."

As I surveyed the area Rinaldi had indicated, the bully pressed harder on my chest. More than ten years of seasonal flooding. There wouldn't be a single indicator. No depression. No insect activity. No modified vegetation. No stratigraphy. Nothing to hint at an underground cache.

Claudel looked a question at me. Behind him the stream burbled softly. Overhead a crow cawed and another answered.

"If they're here, I'll find them," I said with more confidence than I felt.

The cawing sounded like laughter.

By noon we'd cleared vegetation and debise from an area approximately fifty yards by fifty yards, based on Frog's hazy recollection of the grave locations. It turned out he'd never actually seen the bodies, but was going on "reliable information." According to gang lore the victims had been invited for a lawn party; then marched into the woods and shot in the head. Terrific.

I'd marked off a search grid, then set orange plastic stakes along the boundaries at five-foot intervals. Since bodies are rarely stashed below six feet, I'd requested a ground-penetrating radar unit with a 500 MHz antenna, a frequency effective at those depths. It had arrived within the hour.

Working with the radar operator, I'd dug a test pit outside the search area to allow assessment of density, moisture content, layer changes, and other soil conditions. We had refilled the hole, burying in it a length of metal rebar. The operator had then scanned the pit for control data.

He was completing the final tuning of his equipment when Frog got out of the Jeep and sidled over to me, followed closely by his guard. It was one of several forays he'd made, the sniper-free morning having allayed his anxiety.

"What the fuck is that?" he asked, indicating a set of devices that looked like a contraption from Back to the Future. Just then Claudel joined us.

"Frog, you could benefit from some new adjectives. Maybe get one of those calendars that shows you a different word every day."

"Fuck you."

In a way I appreciated the English expletives. They were like sounds of home in a foreign land.

I looked to see if Frog was merely cracking wise, but the pale green eyes suggested a genuine interest. O.K. Where he was going Frog wouldn't be having a lot of scientifically broadening experiences.

"It's a GPR system."

He looked blank.

"Ground-penetrating radar."

I pointed to a terminal plugged into the cigarette lighter of a four-wheel-drive vehicle.

"That's the GPR machine. It evaluates signals sent from an antenna, and produces a pattern on that screen."

I indicated a sledlike structure with an upright handle and a long, thick cable connecting it to the GPR box. "That's the antenna."

"Looks like a lawn mower.

"Yeah." I wondered what Frog knew about lawn care. "When an operator pulls the antenna across the ground it transmits a penetrating signal, then sends data to the GPR machine. The radar machine evaluates the strength and rebound time of the signal."

He looked as if he was with me. Though pretending disinterest, Claudel was also listening.

"If there is something in the soil, the signal is distorted. Its strength is affected by the size of the underground disturbance, and by the electrical properties at the upper and lower boundaries. The depth of the feature determines how long the signal takes to go down and back."

"So this thing can tell you where you've got a stiff?"

"Not a body specifically But it can tell you there's a subsurface disturbance, and it can provide information about its size and location."

Frog looked blank.

"When you dig a hole and put something in it, the spot is never the same as it was before. The fill may have less density, a different mix, or different electrical properties from the surrounding matrix."

True. But I doubted that wouid be the case here. Ten years of water seepage has a way of obliterating soil differences.

"And the thing that's been buried, whether it's a cable, unexploded ordnance, or a human body, will not send the same signal as the soil around it."

"Ashes to ashes. What if the corpse has oozed into tomorrow's drinking water?"

Good question, Frog.

"The decomposition of flesh can change the chemical composition and electrical properties of dirt, so even bones and putrefied corpses may show up.