Death's Acre: Inside The Legendary Forensic Lab The Body Farm by Bill Bass (essential books to read txt) 📕

When Brown had first contacted me, he’d mentioned that there were indications the cremains from Tri-State might include cement powder, because the authorities’ search of the facility turned up numerous bags of cement. Cement looks very similar to the ash that results from incinerating and pulverizing human bones, so it seemed possible that the crematorium might resort to sending families bags of cement powder if they didn’t have genuine cremains to send. I searched the scientific literature to find if there was an easy test I could do for the presence of cement.

Cement is mostly powdered limestone, or calcium carbonate. One quick test geologists use to tell if a rock is limestone is to squirt a drop or two of hydrochloric acid on the rock. If the liquid fizzes when it hits the rock, they know it’s limestone.

I’d obtained a small quantity of dilute hydrochloric acid, which was sealed in a medicine bottle with an eyedropper. Carefully, I sucked up a few drops into the dropper’s rubber bulb and squeezed them onto a small mound of powder I’d put on a metal tray. As soon as the drops hit the powder, they fizzed and bubbled. It looks like this might be cement, I thought, or powdered limestone, anyhow.

I made one last phone call, to Dr. Al Hazari, a UT chemistry professor I’d known and respected for years. Al agreed to obtain a more detailed chemical analysis of the powdery material; at his direction, I rescreened the cremains another five times to be sure it was free of larger pieces and to mix it uniformly. Then I scooped out 42 grams—about an ounce and a half—sealed it in a small vial, and took it over to the chemistry department.

With any luck, we’d be able to tell the Harden family more soon.

IT DIDN’T TAKE LONG to hear back from my colleague in the Forest Products Center. The sample I’d taken him was burned plywood, he said. That was neither surprising nor disturbing: The cardboard cartons in which bodies are generally shipped and cremated have a thin plywood floor, so they can support the weight of the corpse when the carton is picked up. Without it, the carton might buckle or tear, especially if fluids have seeped from the body.

My textile expert’s report on the fuzz balls told me they were a synthetic material—probably polypropylene, he said. Polypropylene is an incredibly versatile plastic. Molded or cast as a solid material, it’s used to make things ranging from dishwasher-safe food-storage containers to automobile bumpers. Spun into fibers, it’s made into outdoor carpeting, floating marine ropes, and tearproof FedEx envelopes.

Polypropylene is light, strong, tough, and versatile, but it’s not heat-resistant. Its melting point isn’t much above 300 degrees Fahrenheit—less than the temperature at which chocolate-chip cookies bake, let alone the fierce heat required to burn a body. Accidentally or intentionally, the fuzz balls had clearly been added after Chigger Harden’s body was cremated.

If, that is, Chigger’s body had been cremated. Clearly the sample contained fragments of burned human bones. But were they Lloyd Harden’s bones or someone else’s? If DNA could survive the cremation process, we could answer that question definitively. Unfortunately, cremation, if done right, burns all the organic material in bone. In a process called calcining, bone is reduced to its primary mineral building block, calcium. The carbon-based DNA molecules—like the carbon in a cardboard coffin or a cotton shirt—burn up completely. Chemically, all traces of human life and identity go up in smoke. So the bulk of our sample—that 2.9 pounds of ashy material remaining after the rusted staple and charred fabric and fuzz balls were sifted out—couldn’t tell us whether this was Chigger Harden. All it could tell us was whether most of it was, or had been, a human being.

On April 30, I received the results of the chemical analysis. My chemist colleague Hazari had hit upon an ingeniously simple test to suggest whether the material was human. The human body has a fairly consistent chemical composition. At some point during our school years, most of us learn that the body is mostly water—roughly 60 percent by weight. The other 40 percent is divided among a host of other elements, mainly calcium and carbon. (If humans had ingredient labels, like prepackaged foods in the grocery store, our list of ingredients might start out as follows: water, calcium, carbon . . .)

One ingredient that’s practically last on the body’s list is silicon. On average, the human body contains just 18 grams of it, or about two-thirds of an ounce. If you evaporate all the body’s water and burn off all its carbon in a cremation furnace, you’re likely to end up with 5 or 6 pounds of cremains, of which silicon represents less than 1 percent by weight.

Hazari had sent my 42-gram sample to a certified commercial lab in Knoxville called Galbraith Laboratories (“Accuracy with Speed—Since 1950”). He could have tested it himself in a chemistry lab at the university, but a certified lab’s precision is frequently tested and well documented, and we wanted to be sure the analysis would hold up in court. A Galbraith technician ran the sample through a spectrographic test called “ICP-OES,” short for “inductively coupled plasma optical emission spectroscopy.” The ICP part of the procedure burns an unknown material in argon gas, glowing brightly at 18,000 degrees Fahrenheit. Then the OES instrument “fingerprints” the sample, essentially, by reading the wavelengths of the light given off as the sample burns. The final step is to compare the sample’s optical fingerprint with those of known elements. It’s an analytical chemist’s version of the way an FBI fingerprint analyst compares a crime scene print with a database of prints from known criminals.

According to Galbraith Laboratories’ analysis, the cremains identified by Tri-State as Chigger’s were more than 15 percent silicon. Unless he’d been eating a lot of dirt just before he died, that reading was a lot higher than it should have