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

in murders anywhere in the world, any time of the year. It doesn’t vary—not the sequence, that is. What does vary, and dramatically, is the timing. And the main variable that affects timing is temperature.

On one level that’s just plain common sense, of course: a warm body’s going to decompose faster than a cold one. I used to tell my students, “That’s why you keep meat in the refrigerator, not in your kitchen cabinet.” Higher temperature speeds up the work of bacteria as a body putrefies. It also promotes greater insect activity. Bugs, like people, prefer to picnic in the summertime. But to take things from the level of common sense to the level of scientific precision took us years of research into decomposition rates, and how those rates vary with temperature and humidity. Eventually we derived a mathematical formula that quantified all our observations. That formula, coupled with crime scene weather data, allowed us to calculate time since death no matter how the temperatures varied.

The key was a unit of measure called “accumulated degree days,” or ADDs: simply put, the running total of the average daily temperature. For example, ten consecutive 70-degree days in summertime would total 700 ADDs; so would 20 wintertime days averaging 35 degrees apiece. In either season, winter or summer, a body at 700 accumulated degree days would exhibit similar signs of decomposition: bloating, “marbling” (distension and scarlet coloration of the veins), skin slippage, and leaching of volatile fatty acids. In our experiments at the Body Farm, we measured ADDs forward in time from the moment of death, noting what stage of decomp corresponded to a given number of ADDs. In an actual forensic case, we performed that same process in reverse, backtracking through the crime scene weather data until we reached the date when the ADDs corresponded with the actual state of decay of a body discovered at a crime scene.

In this case, the crime scene photos showed me that the Perry bodies were moving into the advanced stage of decomposition, in which bloating subsides and the tissues undergo most of their breakdown and liquefaction. In my best judgment the decomposition of the Perrys’ bodies indicated they were at approximately 800 ADDs. The next step was to learn what sort of weather they’d had in Mississippi during the weeks before the bodies were found.

I asked Bill Goodwin to send me Magnolia’s temperature readings for the months of November and December. Those numbers indicated that it had been a pretty chilly fall. On eight separate nights between mid-November and mid-December, the temperature had dropped to freezing or below. Backtracking in time and temperature, I concluded that the family had been killed somewhere between twenty-five and thirty-five days before they were found.

But there was one thing that didn’t quite fit with that picture: the maggots. The bodies were covered with maggots, the larvae of blowflies. Just as bacteria consume a body from the inside out, blowflies start on the outside and eat their way in. Between the microscopic bugs and the macroscopic ones, nature is extremely efficient at reclaiming us: during a hot Tennessee summer, a fresh body can be reduced to bare bone in as little as two weeks. A swarm of maggots covered the faces of Darryl and Annie. Much of the flesh was gone, exposing their skulls beneath. The maggots were also massed at a number of other locations, which corresponded to the autopsy’s findings of knife wounds—and therefore blood.

Blowflies love blood. They can smell it miles away. If there’s a lot of blood and the weather’s warm, they can converge on a body by the thousands. They feed and they lay eggs, which can hatch into maggots just a few hours later.

Darryl had defensive wounds on his hands as well as the fatal wounds to his chest and abdomen. Annie had eight stab wounds in various parts of her body. All of these showed intense maggot activity. So did Krystal’s genitals—just the sort of dark, moist opening the insects like. The rest of her body was not as badly decomposed as her parents’, and for two reasons: Being much smaller and slimmer than her parents, she would naturally decompose more slowly, a phenomenon we observed many times in our studies at the Body Farm. And because she was strangled, rather than stabbed, there was no blood, so she was less appealing to the flies and maggots.

Some of the maggots I saw in the crime scene photos were a half-inch long, a stage entomologists call the “third instar”; in plain language, that means they were fully mature and close to metamorphosing into pupae and then adult flies. That told me that the maggots had hatched from eggs laid approximately two weeks before. I knew that because of studies we did at the Body Farm in the 1980s. A Ph.D. student of mine, Bill Rodriguez, spent months studying the order and the timing of insect activity in human corpses.

But no matter how closely I looked—with my naked eye and with a magnifying glass—the one thing I didn’t see in the photos was a single empty pupa casing. This complicated things. The state of decomposition indicated to me that the Perrys had been killed in mid-November. But the maggots—and the absence of pupa casings—suggested that the murders had occurred around December 2. And the suspect—the defendant—had an alibi from December 2 onward. The prosecution had its work cut out for it. So did I.

Goodwin had first called me on May 18. Two weeks later I made the ten-hour drive to Mississippi for the trial of the man suspected of murdering the Perry family.

DARRYL, Annie, and Krystal Perry had lived in a New Orleans suburb called Marrero; so did Darryl’s mother, Doris Rubenstein, and her husband, Michael, a cabdriver. In the early 1990s, Michael—Mike—had bought a small cabin 120 miles north, in Summit (elevation 431 feet), as a place for quiet weekend getaways. In November of 1993 the Perrys went up to stay there.

On November 5,