Without Mercy by Jefferson Bass Page A

vertical structure of the mouth—a white male, of middle age. Trouble was, there were no middle-aged white malesmissing in Loudon County, or anywhere within a hundred miles of Loudon County.
    At the time, my colleague Richard had just put the finishing touches on the first version of ForDisc. ForDisc was short for Forensic Discriminant Functions, a mouthful of a name that referred to the complicated algorithms, or equations, that Richard had written to calculate what racial group a particular skeleton best matched. To create a basis for comparison, Richard, along with helpful students and colleagues worldwide, had keyed thousands and thousands of measurements into ForDisc, from skeletons around the globe. As it happened, on that very day—long past, yet still vivid in my memory—I had grumbled about the lack of progress in identifying the John Doe from Polecat Creek. “Let’s see what ForDisc says about him,” Richard suggested. With an indulgent smile I handed over the bones, knowing that ForDisc would agree with me.
    But ForDisc didn’t agree with me. I had focused almost entirely on the Polecat Creek victim’s skull, but ForDisc also considered measurements from the postcranial skeleton, the bones below the skull. On the basis of the postcranial elements, ForDisc judged the Polecat Creek victim to be African American, or perhaps mixed race. And sure enough, when the detective checked missing-person reports for African Americans instead of whites, he hit pay dirt immediately: A black man from Oak Ridge had gone missing a year or so before, and when we compared his dental records with the teeth from our victim, they matched perfectly. Brockton 0, ForDisc 1. Fortunately, ForDisc and I had agreed on virtually everything since Polecat Creek, but Polecat Creek had taught me the value of a second opinion, even if that opinion came from a bunch of circuit boards and arcane formulas.
    Ever since Polecat Creek, I’d always been open to whatever light ForDisc could shed on an unknown skeleton. In the Cooke County case, though, ForDisc would likely be as clueless and hamstrung as I was.
    Quit whining , I chided myself. The only way forward is forward. Step by step . The first step for case 16–17 was some quick orthopedic surgery. Normally I would do a bit of dental work instead, but here, too, I was thwarted by the lack of a skull. My kingdom for a skull, I silently declaimed. I had promised to send a DNA sample to the TBI lab, and teeth generally provide the best DNA samples. Tooth enamel does a good job of encapsulating and protecting the genetic material from potential damage by weather, bacteria, and other environmental or chemical factors. But there were no teeth; hence the orthopedic surgery: A bone sample would have to do.
    Reaching up to a tool rack above one of the lab’s counters, I took down a motorized implement that resembled a Dremel tool—a heavy, chrome-plated version, pumped up on steroids. A slender shaft projected from one end of the stainless housing, and attached to the shaft at a right angle was a flat, asymmetrical blade, one whose fanlike shape never failed to put me in mind of a ginkgo leaf, though I’d never seen tiny teeth rimming the curve of a ginkgo leaf. Hefting the tool, a Stryker autopsy saw, I felt weight, solidity, and power. I flicked the switch, and with a hum and a jolt it kicked on, the edge of the blade twitching in rapid, almost invisible oscillations.
    Slowly I moved the vibrating blade toward my own forearm—closer and closer, millimeter by millimeter—and touched it to the flesh midway between my wrist and elbow. The blade buzzed and tickled, but it did not cut, my pale skin oscillating in perfect sync with the minuscule movements of the tiny teeth. This was one of the wondrous things aboutthe Stryker saw: it could slice through bone like a hot knife through butter, but it wouldn’t cut soft tissue, not unless the soft tissue