That let me in for a harrowing two days of rappeling to the water's edge, balancing on ice-covered rocks as I used a paintbrush to ease human ash out of the crevices and into a dustpan, then transferred all of it to plastic boxes lined with a cushion of toilet paper. Meanwhile, the police brought in a team of scuba divers from Louisville to check out the river bottom, where they recovered a few more bone fragments.

Back at the lab, I was faced with the daunting task of sifting through some eighty pounds of ash mixed with dirt and fire debris. All of us knew who these victims were-but I was the one who had to prove it, hopefully while finding enough evidence to allow the medical examiner to confirm a cause and manner of death.

By this point, I knew that the largest and most revealing pieces of bone had been recovered from the riverbank, so I opened those boxes first, carefully lifting out the forty-three bone fragments, one by one, onto a clean white sheet of butcher paper. When I saw two complete femoral heads, each from the top end of a right thighbone, I knew we had the remains of two people. But I couldn't yet prove who they were. Philip had found Gary and Sophie's medical and dental records, but I hadn't yet found any teeth or bone fragments that I could match to them.

The sorting process was slow and tedious, but I figured out how x-rays might help. I transferred scoops of ash onto a fiberglass cafeteria-style tray, gently smoothing the debris with my fingertips until it was only an inch thick. Then I took an x-ray of the tray, looking at the films to spot the difference between bone, wood, and metal. When I spotted something that piqued my interest, I could lay the x-ray film right on top of the tray, pinpointing the location of the exact piece I wanted.

I sifted my way through hundreds of scoops of ash, picking out several large pieces of bone, teeth, and metal chunks. Then, after about twelve hours of this sorting process, I saw something that made my heart stop. There on an x-ray was a U-shaped piece of metal with serrated edges. From my former career in orthopedics, I knew I had come upon a surgical fixation staple, most often used to repair or reconstruct ligaments in the knee. I found it hidden in the tray full of ash and rinsed it off well enough to see the engraved logo of the manufacturer and the model number.

I sprinted from the lab to my office, reaching for the pile of medical records stacked up on my desk. I searched desperately for proof of knee surgery-and there it was. Gary Stephens had undergone knee ligament repair in Knoxville just a few years earlier. A quick call to his doctor confirmed that the staple used in the operation was the exact same make, model, and size as the one I'd found.

One positive ID down and one to go. With a fresh wave of enthusiasm, I continued to x-ray several dozen more trays of debris, hoping to identify Sophie. It was a slow, unrewarding process as the x-rays turned up a discouraging number of dead ends-bits of metal that turned out to be zipper teeth, jean rivets, and even a couple of bootlace hooks.

True, I'd also recovered several small pellets of bird shot. But it's not that unusual to find loose shotgun pellets or even bullets in the homes, vehicles, or pockets of Kentucky 's rural residents, so the shot was hardly proof of murder.

Then I did see something useful: a pellet of bird shot actually embedded in a fragment of bone from the spine. Holding my breath, I delicately flicked away the surrounding ash and smiled triumphantly. I now had proof that at least one of the victims had been shot.

There was still no proof that any of these ashes had once been Sophie's, however. And by noon of the third day, I was starting to lose hope. The only evidence that remained was the bucket of debris that we'd rinsed out of the pickup truck, and I'd already looked at that the first night, as it was dripping onto the screen. I hadn't seen anything important then and I didn't expect to find anything now.

Of course, now I had the advantage of x-ray vision. So I continued with my routine of scooping the ash, spreading it out, and scanning the x-rays. Hours passed without results. Then, as I was processing the very last handful of ash, I saw a strange silhouette-like nothing I'd seen in the previous three dozen x-rays. After I'd placed the film on top of the tray and filtered carefully through the mess, my fingertips seized on a small hard object. It was black and covered with ash, and I didn't recognize it until I rinsed it off in the sink. Then I breathed a final sigh of relief. There in my hand was the porcelain crown of a tooth-the very crown I could see on Sophie's dental records.

Now both victims had been identified and we could also prove that at least one of them had been shot in the back. The arson specialist could testify that someone had intentionally incinerated human bodies in the woods and I could attest that the ashes of two people had been thrown into the river. One of these was Gary Stephens. I could also prove that human bones and teeth had been found in the Stephenses' pickup truck, and that one tooth fragment belonged to Sophie.

Though it was impossible to completely separate the remains, it seemed appropriate to bury the husband and wife together, intermingled in death as they had been bound in life. When their son Gary was charged with their murders, he insisted on his innocence, but after he was faced with an impending death penalty trial in the autumn of 2002, he finally pled guilty and was sentenced to life imprisonment.

The “Ashes to Ashes” case taught me a valuable lesson-no detail is too small to be useful, especially when you're dealing with victims who have been destroyed by fire. Like the other cases in this chapter, it points out the many difficulties faced by those of us who try to identify human remains. These cases are hard enough when you are dealing with one victim at a time. When you throw in an explosion, a huge fire, and several dozen victims-the standard recipe for any mass fatality-identifying individuals becomes even more of a challenge. Yet, whether you're dealing with one victim or several hundred, the rules remain the same: Go slow, keep an eye out for details-and always be prepared to be surprised.

7. Oklahoma City

THE PLANE WAS JUST COMING in for a landing as I stuffed the academic journals into my briefcase. I'd already gone over them a hundred times back in Kentucky-after all, I myself had written several of these articles, and since I'd gotten the call from the FBI two days before, I'd reviewed them again and again-but I wanted to be sure I knew this material backward and forward. The FBI had called me in as a consultant on one of the largest law enforcement investigations in U.S. history-the bombing of the Murrah Federal Building in Oklahoma City -and I was taking no chances on not knowing my stuff.

It was August 31, 1995, and the FBI investigation into the bombing had been going on for four and a half months now. Danny Greathouse, the special agent in charge of the FBI's Disaster Identification Unit, had called me when the investigation first began. There were plenty of forensic specialists available-the ones that the FBI usually consulted at the Armed Forces Institute of Pathology (AFIP) and the Smithsonian Institution, as well as the excellent staff at the Oklahoma City Medical Examiner's Office. However, because I'd already worked one sensitive case for the FBI, at Waco, Special Agent Greathouse wanted to be sure he had backup if he needed it.

The victim identification process had continued on without me and I didn't think I'd be involved in the case. Then, two days ago, Special Agent Greathouse had called again, telling me to expect a call from Dr. Douglas Ubelaker. This time they didn't just need backup-they needed me. A major point in the case turned on the racial identification of a single dismembered leg, and Dr. Ubelaker knew that I'd published one article and a large section of my doctoral dissertation on the racial characteristics of the intercondylar notch, a portion of the distal femur at the knee. By one of those odd coincidences that seem to happen so often in my life, the very discovery I'd made when I'd solved the puzzle in Dr. Bass's class was the exact piece of knowledge that was needed here.