"How old are they?"

I inquired, as she opened the oven door.

"Jason is sixteen, Michael fourteen. Debbie is the oldest."

Looking around for the potholders, she turned off the oven, then set a quiche on top of a burner. Her hands trembled as she got a knife and spatula from a drawer "Would you like wine, tea, coffee? This is very light. I did throw together a fruit salad. Thought we'd sit out on the porch. I hope that will be all right."

"'That would be lovely," I replied. "And coffee would be fine."

Distracted, she opened the freezer and got out a bag of Irish Creme, which she measured into the drip coffee maker. I watched her without speaking. She was desperate. Husband and sons were not home. Her daughter was missing, the house empty and silent She did not begin to ask questions until we were on the porch, sliding glass doors open wide, the river curving beyond us glinting in the sun.

"What the dogs did, Dr. Scarpetta, "she began, picking at her salad. " Can you offer an interpretation?"

I could, but I did not want to.

"Obviously, the one dog got upset. But the other one didn't?"

Her observation was posed as a question.

The other dog, Salty, had indeed reacted very differently than Neptune had. After he sniffed the driver's seat, Gail hooked the lead on his harness and commanded, "Find."

The dog took off like a greyhound. He snuffled across the exit ramp and up through the picnic area. Then he tugged Gail across the parking lot toward the Interstate and would have gotten a nose full of traffic had she not yelled, "Heel!"

I had watched them trot along the wooded strip separating west lanes from east, then across pavement, heading straight for the rest stop opposite the one where Deborah's Jeep had been found. The bloodhound finally lost the scent in the parking lot.

"Am I to believe," Mrs. Harvey continued, "that whoever was driving Debbie's Jeep last got out, cut through the westbound rest stop, and crossed the Interstate? Then this person most likely got into a car parked in the eastbound rest stop and drove away?"

"That is one possible interpretation," I replied, picking at my quiche.

"What other possible interpretation is there, Dr. Scarpetta?"

"The bloodhound picked up a scent. As for the scent of who or what, I don't know. It could have been Deborah's scent, Fred's scent, the scent of a third person - "

"Her Jeep was sitting out there for hours," Mrs. Harvey interrupted, staring off at the river. "I suppose, anybody could have gotten in to look for money, valuables. A hitchhiker, transient, someone on foot who crossed over to the other side of the Interstate afterward."

I did not remind her of the obvious. The police had found Fred Cheney's wallet in the glove compartment, complete with credit cards and thirty-five dollars cash. It dd not appear that the young couples' luggage had been gone through. As far as anyone could tell, nothing was missing from the Jeep except its occupants and Deborah's purse.

"The way the first dog acted," she went on matter-of-factly. "I assume this is unusual. Something frightened. Upset him, at any rate. A different smell - not the same scent the other dog picked up. The seat where Debbie may have been sitting…"

Her voice trailed off as she met my eyes.

"Yes. It appears that the two dogs picked up different scents."

"Dr. Scarpetta, I'm asking you to be direct with me."

Her voice trembled. "Don't spare my feelings. Please. I know the dog wouldn't have gotten so upset unless there was a reason. Certainly, your work has exposed you to search-and-rescue efforts, to bloodhounds. Have you ever seen this before, the way the dog reacted?"

I had. Twice. Once was when a bloodhound sniffed car trunk that, as it turned out, had been used to transport a murder victim whose body had been found inside a Dumpster. The other was when a scent led to an area along a hiking trail where a woman had been raped and shot.

What I said was "Bloodhounds tend to have strong reactions to pheromonal scents."

"I beg your pardon?"

She looked bewildered.

"Secretions. Animals, insects, secrete chemicals. Sex attractants, for example," I dispassionately explained. "You're familiar with dogs-marking their territory or attacking when they smell fear?"

She just stared at me.

"When someone is sexually aroused, anxious, or afraid, there are various hormonal changes that occur in the body. It is theorized that scent-discriminating animals, such as bloodhounds, can smell the pheromones, or chemicals, that special glands in our bodies secrete - "

She cut me off. "Debbie complained of cramps shortly before Michael, Jason, and I left for the beach. She had just started her period. Could that explain…? Well, if she were sitting in the passenger's seat, perhaps this was the scent the dog picked up?"

I did not reply. What she was suggesting could not account for the dog's extreme distress.

"It's not enough."

Pat Harvey looked away from me and twisted the linen napkin in her lap. "Not enough to explain why the dog started whining, the fur stood up on his back. Oh, dear God. It's like the other couples, isn't it?"

"I can't say that."

"But you're thinking it. The police are thinking it. If it hadn't been on everybody's mind from the start, you never would have been called yesterday. I want to know what happened to them. To those other couples."

I said nothing.

"According to what I've read," she pushed, "you were present at every scene, called there by the police."

"I was."

Reaching into a pocket of her blazer, she withdrew a sheet of legal paper and smoothed it open.

"Bruce Phillips and Judy Roberts," she began to brief me, as if I needed it. "High school sweethearts who disappeared two and a half years ago on June first when they drove away from a friend's house in Gloucester and never arrived at their respective homes. The next morning Bruce's Camaro was found abandoned off U.S. Seventeen, keys in the ignition, doors unlocked, and windows rolled down. Ten weeks later, you were called to a wooded area one mile east of the York River State Park, where hunters had discovered two partially skeletonized bodies facedown in the leaves, approximately four miles from where Bruce's car had been found ten weeks earlier."

I recalled that it was at this time VICAP was asked by the local police to assist. What Marino, Wesley, and the detective from Gloucester did not know was that a second couple had been reported missing in July, a month after Bruce and Judy had vanished.

"Next we have Jim Freeman and Bonnie Smyth," Mrs. Harvey glanced up at me. "They disappeared the last Saturday, in July after a pool party at the Freemans' Providence Forge home. Late that evening Jim gave Bonnie a ride home, and the following day a Charles City police officer found Jim's Blazer abandoned some ten miles from the Freeman home. Four months after that, on November twelfth, hunters in West Point found then bodies…"

What I suspected she did not know, I thought, unpleasantly, was that despite my repeated requests, I was not given copies of the confidential sections of the police reports, scene photographs, or inventories of evidence. I attributed the apparent lack of co-operation to what had become a multi-jurisdictional investigation.

Mrs. Harvey continued relentlessly. In March of the following year, it happened again. Ben Anderson had driven from Arlington to meet his girlfriend, Carolyn Bennett, at her family's home in Stingray Point on the Chesapeake Bay. They pulled away from the Andersons' house shortly before seven o'clock to begin the drive back to Old Dominion University in Norfolk, where they were juniors. The next night a state trooper contacted Ben's parents and reported that their son's Dodge pickup truck had been found abandoned on the shoulder of 1-64, approximately five miles east of Buckroe Beach. Keys were in the ignition, the doors unlocked, and Carolyn's pocketbook was beneath the passenger's seat. Their partially skeletonized bodies were discovered six months later, during deer season in a wooded area three miles of Route I99 in York County. This time, I did not even get a copy of the police report.