I DID NOT GO TO THE S WAIN C OUNTY COURTHOUSE ON M ONDAY. Instead, I recrossed the mountains west to Tennessee, and by midmorning was approximately thirty miles northwest of Knoxville, approaching the entrance to the Oak Ridge National Laboratory. The day was wet and gloomy, and my wipers slapped a steady cadence back and forth, clearing two fans on the misty windshield.

Through the side window I could see an old woman and toddler feeding swans on the bank of a small lagoon. At the age of ten I'd had a run-in with an ugly duckling that could have taken out a commando force. I questioned the wisdom of their outing.

After showing ID at a guardhouse, I drove across a vast parking area to the reception center. My host was waiting, signed me in, and we returned to the car. Another hundred yards, and my new ORNL badge and license plates were verified at a third checkpoint before I was allowed to pass through a chain-link fence surrounding the compound.

“Pretty tight security. I thought this was Department of Energy.”

“It is. Most of the work involves energy conservation, computers and robotics, biomedical and environmental conservation, medical radioisotope development, that sort of thing. We maintain security to protect DOE intellectual property and physical equipment. There's also a high-flux isotope reactor on-site.”

Laslo Sparkes was in his thirties but already nurturing a stout paunch. He had short, slightly bowed limbs and a round face, pockmarked on the cheeks.

Oak Ridge began as a World War II wonder baby, constructed in just three short months in 1943. Thousands were dying in Europe and Asia, and Enrico Fermi and his colleagues had just achieved nuclear fission in a squash court under the stands of the football stadium at the University of Chicago. Oak Ridge's mission had been simple: build the atomic bomb.

Laslo directed me through a labyrinth of narrow streets. Turn right here. Left. Left. Right. Except for its vast size, the complex looked like an apartment project in the Bronx.

Laslo indicated a dark brick building identical to a score of other dark brick buildings.

“Park here,” he said.

I pulled over and cut the engine.

“I really appreciate your doing this on such short notice.”

“You were there when I asked for help.”

Years earlier, Laslo had needed bone for his master's research in anthropology, and I'd provided samples. We'd kept in touch throughout his doctoral work and during the decade he'd been a research scientist at Oak Ridge.

Laslo waited while I retrieved a small cooler from the trunk, then led me into the building and up the stairs to his lab. The room was small and windowless, every millimeter crammed with battered steel desks, computers, printers, refrigerators, and a million machines that glowed and hummed. Glass vials, water containers, stainless-steel instruments, and boxes of latex gloves lined the countertops, and cardboard cartons and plastic buckets were stacked below.

Laslo led me to a work space in back and reached for the cooler. When I handed it to him, he removed a plastic bag, peeled off the tape, and peeked inside.

“Give this to me again,” he said, sniffing the bag's contents.

As I explained my trek with Lucy Crowe, Laslo poured dirt from the bag into a glass container. Then he began entering information onto a blank form.

“Where did you sample?”

“I collected where the dog indicated, under the wall and under the stones that had fallen out. I figured that soil would be most protected.”

“Good thinking. Normally the corpse acts as a shield for the soil, but stones would have had the same effect.”

“Does rain create problems?”

“In a protected environment the heavy, mucoidlike secretions produced from anaerobic fermentation bind the soil together, making dilutional factors from rainfall insignificant.”

He sounded like he was reading from one of his articles in the Journal of Forensic Sciences.

“Keep it simple, please. This is way off my field.”

“You spotted the decomp stain.”

“Actually, my dog did.” I indicated a plastic vial. “The pupae are what tipped me.”

Laslo withdrew the jar, twisted off the lid, and shook a number of casings into the palm of his hand. Each looked like a miniature football.

“So maggot migration had taken place.”

“ If the stain is from a decomp espisode.” I'd had all night to worry over Boyd's discovery. Though I was sure his nose and my instincts were correct, I wanted proof.

“Maggot pupae definitely suggest the presence of a corpse.” He replaced the casings. “I think your dog was right on.”

“Can you determine if it was an animal?”

“The amount of volatile fatty acids will tell us if the body was over one hundred pounds. Very few mammals get that big.”

“What about hunting? A deer or bear could get that big.”

“Did you find any hairs?”

I shook my head.

“Decaying animals leave behind tons of hair. And bones, of course.”

When an organism dies, scavengers, insects, and microbes take an immediate interest, some munching from the outside, others from within, until the body is reduced to bone. This is known as decomposition.

Ruby would talk in terms of dust to dust, but the process is much more complicated than that.

Muscle, comprising 40 to 50 percent of the weight of a human body, is composed of protein, which is composed of amino acids. At death, the fermentation of fat and protein yields volatile fatty acids, or VFAs, through bacterial action. Inside the gut, other microbes do their part. As putrefaction advances, liquids ooze from the body, carrying with them the VFAs. Death investigators call the mixture soup.

Laslo's research focused at the microbial level, analyzing organic components contained in the dirt under and around a body. Years of work had demonstrated a correlation between the decay process and VFA production.

I watched him filter soil through a stainless-steel sieve.

“Exactly what do you look for in the dirt?”

“I don't use soil, I use soil solution.”

I must have looked blank.

“The liquid component between soil particles. But first I have to clean it.”

He weighed the sample.

“As body fluids flow through, the organic matter becomes bound to the soil. I can't use chemical extractants for separation, because that would partially dissolve the volatile fatty acids from the decomposing body.”

“And alter their measurements.”

“Exactly.”

He placed the soil in a centrifuge tube and added water.

“I use deionized water in a ratio of two to one.”

The tube went onto a vortex for one minute to mix the solution. Then he transferred it to a centrifuge and closed the lid.

“The temperature inside is held at five degrees. I'll centrifuge for forty minutes, then filter the sample to remove any remaining microorganisms. After that it's simple. I'll check the pH, acidify with a formic acid solution, and pop the thing into the gas chromatograph.”

“How about a crash course.”

Laslo finished adjusting settings, then gestured to a desk and we both sat.

“O.K. As you know, I'm looking at the products of muscle and fat breakdown called volatile fatty acids. Are you familiar with the four stages of decomposition?”

Anthropologists and death investigators think of corpses as being in one of four broad stages: fresh, bloated, decayed, or skeletal.

I nodded.

“There's little change in VFAs in a fresh corpse. In the second stage, a body bloats due to anaerobic fermentation, primarily in the gut. This causes skin breakage and the leakage of fermentation byproducts rich in butyric acids.”

“Butyric acids?”

“Volatile fatty acids include forty-one different organic compounds, of which butyric acid is one. Butyric, formic, acetic, propionic, valeric, caproic, and heptanoic are detectable in soil solution because they're soluble in water. Two of them, formic and acetic, are too abundant in nature to be of much use.”

“Formic is the one that causes pain from ant bites, right?”

“That's the one. Caproic and heptanoic are only found in significant amounts during the colder months. Propionic, butyric, and valeric are my boys. They're released from a decomposing corpse and deposited in soil solutions in specific ratios.”

I felt like I was back in Biochem 101.

“Since butyric and propionic acids are formed by anaerobic bacteria in the gut, the levels are high during the bloat stage.”

I nodded.

“Later, during decay, aerobic bacteria join the act.”

“So at stage three there's a surge in all VFA formation.”

“Yes. Then there's a rapid fall-off at the onset of stage four.”

“No flesh, no bacteria.”

“The soup kitchen closes.”

Behind us the centrifuge hummed softly.

“I've also found that all fatty acid values are highest just after maggot migration.”

“When larvae abandon the corpse to pupate.”

“Yes. Until that point the presence of the insects tends to restrict the flow of body fluids into the soil.”

“Doesn't pupation occur at approximately four hundred ADD?” ADD stands for “accumulated degree days,” a figure calculated by summing average daily temperatures.

“With some variation. Which brings up a good point. VFA production is temperature dependent. That's why it can be used to determine time since death.”

“Because a corpse will produce the same ratios of propionic, butyric, and valeric acids for any given accumulated degree days.”

“Exactly. So the volatile fatty acid profile can provide an estimate of TSD.” TSD is the investigator's shorthand for “time since death.”

“Did you get the National Weather Service data?”

He went to a set of shelves and returned with a printout.

“It was amazingly fast. Normally it takes much longer. But we do have a slight problem. For a really accurate TSD estimate I need three things. First, the specific fatty acid ratios.”

He pointed at a computer screen linked to the gas chromatograph.

“We'll have those shortly. Second, the National Weather Service data at the location where the corpse was found.”

He held up the printout.

“Third, information on the weight and condition of the corpse. And you ain't got no body.” He sang the last.

“Everyone's a comedian.”

“Two variables are important: the amount of moisture in the soil, and the weight of the body prior to decomposition. Because everyone has a different ratio of fat and muscle tissue, if I don't have a body, I use a standard of one hundred fifty pounds, then apply a correction factor. I think we're safe in assuming your deceased weighed between one hundred and three hundred pounds?”

“Yes. But in doing this, our range broadens, right?”

“Unfortunately. Did you try a rule-of-thumb estimate?”

Since volatile fatty acid liberation ceases at accumulated degree days 1,285 plus or minus 110, it is possible to obtain a rough estimate of time since death by dividing the average daily temperature on the day a corpse is found into 1,285. I'd done this for Lucy Crowe. Yesterday's average temperature in Bryson City was 18°C (64°F), yielding a maximum time since death of seventy-one days.

“That would be the date on which full skeletonization had taken place, and no more VFAs would be detectable.”

Laslo looked at the wall clock.

“Let's see how accurate you were.”

He rose, filtered and vortexed the soil solution sample, tested its acidity, then placed the tube into the gas chromatograph. After closing and sealing the chamber, and adjusting the settings, he turned back to me.

“Let's give this a few minutes. Coffee?”

When we returned the screen showed a series of peaks in varying colors, and a list of components and their concentrations.

“Each curve shows the concentration of a volatile fatty acid per gram of dry weight of soil. First I'll correct for dilution and soil moisture.”

He hit a few keys.

“Now I can calculate an ADD for each VFA.”

He started with butyric acid.

“Seven hundred accumulated degree days.”

He performed more calculations, using each acid. With one exception the ADDs fell within the 675 to 775 range.

“Now I'll use the National Weather Service data to determine the number of days needed to obtain 675 to 775 accumulated degree days. We may have to adjust later if the readings at your body site differ from the officially recorded temperatures. Normally, I like to know that in advance, but it's not a major problem.”

A few more keystrokes. I held my breath.

“Forty-one to forty-eight days. That's your range. According to your calculation, full skeletonization would have taken place in seventy-one days.”

“So death occurred six to seven weeks ago.”

He nodded. “But keep in mind that this time frame is based on an estimated, not an actual, predeath weight.”

“And at the time the stain was produced, the body was fleshed and actively decomposing.”

He nodded.

“But I ain't got no body.”

“And nobody cares for me.”

* * *

I drove straight to Lucy Crowe's office. The rain had stopped, but dark clouds shouldered each other low over the mountains, jockeying for position with their heavy loads.

I found the sheriff eating a corn dog behind the Civil War desk. Seeing me, she wiped crumbs from her mouth, then arced the stick and wrapper into a trash can across the room.

“Two points,” I said.

“All net. No rim.”

I laid hard copy in front of her and took a chair. She studied the VFA profile a full minute, elbows splayed on the desktop, fingers on her temples. Then she looked up.

“I know you're going to explain this.”

“Volatile fatty acids.”

“Meaning?”

“A body decomposed inside that wall.”

“Whose?”

“The VFA ratios suggest a time since death of six to seven weeks. Daniel Wahnetah was last seen in late July, reported missing in August. It's now October. Do the math.”

“Assuming I accept that premise, which I don't necessarily, how did Wahnetah's foot get to the crash scene?”

“If Boyd smelled decomposition, so could coyotes. They probably dragged the foot from under the wall. There's room where the foundation has crumbled.”

“And left the rest of him?”

“They probably couldn't detach anything else.”

“And how did Wahnetah get inside the courtyard?”

I shrugged.

“And how did he die?”

“That's sheriffing. I do the science.”

Down the hall Hank Williams crooned the “Long-Gone Lonesome Blues.” Static made the music sound like it was coming from another era.

“Is this enough for a warrant?” I asked.

The sheriff studied the paper for another full minute. Finally she looked up, the eyes to die for hard on mine. Then she reached for the phone.

* * *

By the time I left the sheriff 's office a light rain was falling. Headlights, stoplights, and neon signs twinkled and shimmered in the dusk of early evening. The air was heavy with the smell of skunk.

Outside at High Ridge House, Boyd lay in his doghouse, chin on paws, gazing at the raindrops. He raised his head when I called and gave me a look to indicate I should do something. Seeing that I wasn't, he sighed noisily and settled back down. I filled his dish and left him to ponder his sodden world.

Inside, the house was still. I climbed the stairs to the slow ticktick-tick of Ruby's hall clock. No sound came from any bedroom.

Rounding the corner at my end of the hall, I was surprised to see the door to Magnolia slightly ajar. I pushed it inward. And froze.

The drawers in my room had been rifled, the bed stripped. My briefcase had been emptied, and papers and manila folders lay scattered across the floor.

My mind locked on one word.

No! No! No!

I tossed my purse on the bed, flew to the wardrobe, and threw open the doors.

My laptop sat tucked in back, exactly as I'd left it. I pulled it out and clicked it on, my mind still racing.

What was in the room? What was in the room? What was in the room?

Quick mental inventory. Car keys. Credit cards. Driver's license. Passport. All had been with me.

Why? Why? Why?

A quick ransack for valuables, or was someone after something specific? What was there that anyone would want?

What? What? What?

When the computer booted I checked a few files. Everything seemed fine.

I went to the bathroom and splashed cold water on my face. Then I closed my eyes and played a childhood game I knew would calm me. Silently, I ran through the lyrics of the first song to come to mind. “Honky Tonk Women.”

The time-out with Mick and the Stones worked. Steadier, I returned and began gathering papers.

I was still filing when I heard a knock, and opened the door to Andrew Ryan. He held two DoveBars in his right hand.

Ryan's eyes swept the mess.

“What the fuck went on in here?”

I just looked at him, not trusting my voice.

“Is anything missing?”

I swallowed.

“The only thing of value was the computer, and they left that.”

“Pretty much rules out robbery.”

“Unless the intruder was interrupted.”

“Looks like they tossed the place looking for something.”

“Or just to be ornery.”

Why?

“Ice cream?” Ryan offered.

We ate our DoveBars and considered possible explanations. None was persuasive. The two most likely were someone looking for money or someone letting me know he or she didn't care for me.

When Ryan had gone, I stacked the remaining folders and went to run a bath. Throwing back the shower curtain, I got my next shock.

Ruby's ceramic figurine of Orphan Annie lay at the bottom of the tub, her face smashed, her limbs shattered. Sandy dangled from the showerhead, a makeshift noose tight around his neck.

Again, my mind flew, my hands trembled. This message had nothing to do with money. Someone clearly didn't care for me.

Suddenly, I remembered the Volvo. Was that episode a threat? Was this intrusion another? I fought the impulse to run down the hall to Ryan's room.

I considered the lockless doors and thought about bringing Boyd inside. Then who would be threatened?

An hour later, lying in bed and somewhat more logical, I reflected on the strength of my reaction to the invasion of my space. Had it been anger or fear that had sent me over the edge? At whom should I be angry? What should I fear?

Sleep did not come easily.