Unnatural Selection (19 page)

Could it have happened again? Only whatever it was, if there really was anything, had sounded bigger than any seagull. Well, she wasn’t going out into that passageway this time, not in this nasty murk. She’d once seen a big rat running around out there, or rather heard a rat, or something that sounded like a rat. The whole thing was probably just her dream anyway-this awful fog had upset her mental balance-and if it wasn’t, let somebody else find it this time.

She gathered up the pieces of the broken teacup with a wet cloth, shrugged into her still-damp coat, and went home.

A cheerful, softly whistling Gideon Oliver arranged the bones into as near a proper anatomical relationship as the remains would allow. What with Robb’s delivery of the final two sacks yesterday, there was quite a lot of material now, more than he’d realized. The skull and pelvis were lacking, yes, but he guessed he had something close to forty percent of the skeleton laid out on the table in front of him. Plenty to work with.

Because it was nine o’clock and the police department was open to the public for its daily hour, Robb and Clapper were busy with island police matters (a report of a lost cat, a complaint about a neighbor’s wind chimes), and he was on his own, which suited him. Not that he really minded their being around, but this way he could mumble, exclaim, and go “Hm” to his heart’s content without having to explain what he was doing. Things would go faster. He could get right down to business.

And he did. As a serious scientist, a well-regarded expert, a board-certified diplomate in forensic anthropology, the last thing he wanted to do was to examine these remains with the express purpose of determining whether or not they matched the fragmentary description of Pete Williams that he’d heard from Joey last night: age, about thirty; height, about five-ten; build, average.

But of course he was also very much a human being, so naturally it was the first thing he addressed. He started with build, the least specific, least useful, and most unmeasurable of the three characteristics, but also the easiest one on which to reach some conclusion. Inasmuch as bones, especially at muscle-insertion points, reflected muscular development-the bigger and stronger the muscles, the more robust and rugged the bones they attached to-their general ruggedness was an indicator of the muscularity of the living person. And it took but a few moments’ study for him to conclude that this once-living person had been neither especially powerfully built nor particularly puny. In other words: average. Like Williams. Also like almost everybody else. Conclusion: It might indeed be Williams. Or it might not.

Of course “build” comprised more than muscularity. There was also weight. Had the owner of these bones been obese? Skinny? Medium (“average”)? Unfortunately, there was no way to tell. Fat people’s bones looked like thin people’s bones. So no useful decision on that score either.

That left age and height. Stature, as finicky anthropologists (including Gideon) insisted on calling it, was most certainly something you could determine from skeletal remains. You could make an astonishingly good estimate of stature from any of the long bones, including partial ones, or, with a bit less certainty, even from the metacarpals, the finger bones, or the vertebrae. The more of these bones you had, the more accurate the estimate, and Gideon had a lot of them sitting right in front of him. That was the good news. The bad news was that he didn’t carry around in his head or on his person the tables, formulas, and regression equations required to make the calculations. He did carry around-one never knew what one might run into-a copy of ForDisc, a CD containing a sophisticated forensic anthropology computer program from the University of Tennessee that took all the grunt work out of it. You just measured the bones, clicked in the results, grabbed a quick sip of coffee while the computer plugged them into the proper regression formulas, and up popped your stature-range estimates, down to the millimeter. The only problem was, ForDisc was useful only on complete long bones, of which he had nary a one.

There were, however, published formulas for estimating stature from partial long bones; less reliable, naturally enough, but better than pure guesswork. Last night, realizing that he would need them, he had called the departmental secretary and asked her to overnight-mail a couple of textbooks that contained the necessary Steele and McKern formulas. He now also made a mental note to call the museum and ask Madeleine for the sliding and spreading calipers she’d mentioned. An osteometric measuring board was probably out of the question, but it wouldn’t hurt to ask. In any case the formulas wouldn’t arrive until tomorrow, or possibly even the next day, so for the moment there was nothing he could do other than eyeball the bones, which didn’t tell him much. The guy had not been a giant, and he hadn’t been a dwarf-that was about it. Five-ten was very much in the ballpark, but it was a big ballpark. More than that he couldn’t say at this point.

Ageing an adult (and Gideon had already determined these were mature bones, reflecting an age at least in the mid-thirties) was a different matter. No calipers, no formulas, no regression equations, no discriminant function analyses; you just looked carefully at certain skeletal structures, and if you were familiar enough with the changes they typically underwent in adult life, as Gideon was, you could make a respectable guess as to how old the person was when death struck. Not all bones showed these changes with equal clarity. The pubic symphysis-that is, the area where the two halves of the pelvis came together-exhibited them most clearly and predictably (why, exactly, nobody knew), and was therefore the most useful of the skeletal age-indicators, but Gideon didn’t have a pelvis to work with. He did, however, have quite a few ribs-eight, to be exact-and ribs, although not quite as trustworthy as the pelvis, could give you a pretty fair idea of age.

It worked like this: The upper seven ribs did not directly join the sternum-the breastbone-but were connected by struts of cartilage. Without these flexible struts, inflating and deflating the lungs (otherwise known as breathing) would be a far more painful and difficult job than it was. (The next three lower ribs were each connected to the one above, and the lowest two to nothing at all in front.) As one got older, however, this “sternocostal cartilage” began to build up calcium salts and to very slowly ossify, particularly at the end that attached to the rib. As this lifelong process continued, the rib-ends reflected the new stresses placed on them with certain predictable changes. Generally speaking, in going from young to old, they went from billowy-smooth to granular and jagged, from round-rimmed to painfully sharp-rimmed, from flat and wavy to deeply concave. As one of Gideon’s students had put it, “Anybody can tell. They just plain get older- and uglier-looking. Like people.”

So they did, but with some understanding of these characteristics one could do better; one could arrange them into stages and use them for a reasonably reliable estimate of age, within a ten-year range at any rate.

And the estimate that Gideon came up with was fifty, give or take five years; certainly not the thirty he’d been anticipating. He went to pour himself a first cup of coffee from the pot that Robb had made a few minutes earlier (fresh, it wasn’t exactly Starbucks, but it wasn’t sludge either), spooned in some powdered creamer, and talked this over with himself. Could Joey’s guess at Pete Williams’s age have been fifteen or twenty years off? Possible, but very, very unlikely. Or were the rib-ends he’d just looked at atypical and therefore misleading? The standard ranges were, after all, merely averages, not hard-and-fast parameters, and human beings, as everyone who studied them knew, loved to violate averages. Neither Gideon nor any other anthropologist would stake his reputation on an age determination based strictly on his reading of rib-ends or, for that matter, any other single criterion.

But there were other criteria as well, and another ten minutes’ perusal of the bones convinced him that his age estimate had been on target. Aside from the generally “older and uglier” look of the long bones, there were signs of compression and lipping of the lower thoracic vertebrae. (He didn’t have the lumbar vertebrae, in which he’d expect these signs to be even more advanced.) Equally telling, there was some lipping of the glenoid fossa of the scapula-the ovoid depression in which the ball of the humerus nestled, forming the shoulder joint. That was part of the general, unavoidable wear and tear that went along with getting older. And on the body of the scapula-he held it up to the light-yes, there were translucent patches developing; almost like looking through eggshell in places. That went along with getting older, too. Bone demineralized with age, and the scapula, one of the thinnest, flattest bones in the body to begin with, showed it especially clearly.

So everything supported the mid-forties to mid-fifties age range. In any case, the guy was no thirty-year-old, of that he was now certain. The possibility that this was Pete Williams, perhaps a bit strained to begin with, grew even dimmer, despite those oh-so-clever conclusions he’d come up with about supinator crests and squatting facets. A pity, too; it had all fit together so neatly. One more theory that had bitten the dust when faced with the ugly facts. So he was back to square one on identifying the guy.

Ah, well, coming up with a definitive identification was Clapper’s job, not his. All Gideon could do was to provide clues. He topped off his coffee, and went back to take a closer look at something on one of the ribs that had caught his interest.

“That little nick, that insignificant little scratch?” Clapper demanded, staring skeptically at the rib Gideon was holding out to them. “That’s what you brought us in to see, interrupting our vital police work?”

“It sure is, Mike,” said Gideon. “I thought you might have some interest in the cause of death. We’re not simply assuming homicide any more. We have the direct evidence. That’s a knife wound you’re looking at. He was stabbed.”

“It isn’t much to look at,” Robb offered. “You can hardly see it. Just a little ding, really, no more than half an inch long.”

“Not even that,” Gideon said. “Two millimeters in length, and just barely penetrating the cortical bone, the outer layer. But that’s what stab wounds in bone look like. Flesh and organs are easy to penetrate; living bone isn’t. Knife points don’t typically get in very far.”

Robb had taken the magnifying glass that Gideon had offered but Clapper had declined, and was studying the tiny incision. “I see. It isn’t really what you’d call a ding, is it? The edges are very sharp, very straight. And the shape is… well, it’s sort of triangular, isn’t it?”

Gideon nodded. “And judging from that, and from the breadth of it-at the top it’s almost as wide as it is long- I’d say it was probably a fairly big knife with a heavy spine, not some little pocket knife. From the kitchen, possibly something along the lines of an eight- or ten-inch utility knife, although I’m way out on a limb there, so don’t quote me on that.”

Clapper folded his arms. “If you say it’s a stab wound, I’ll accept it, but how can it be the cause of death? Obviously, the rib blocked the knife from entering the body cavity, and you don’t die from a nicked rib, or are you going to tell me that you do?”

“No, of course you don’t, but there’s more. Look.”

He had cleared a space on the table, in which three other ribs lay, and on two of them he pointed out similar nicks. “He didn’t die from these either. But this one…” He slid over the longest of the ribs and held it up for their inspection. “This is the fourth rib on the left side, and here about midway back, you see not a little puncture like the others, but-”

“A spur!” Robb exclaimed. “Like the one on the tibia.”

“Well, not quite. That spur, if you remember, was a stubby little spike on the sawed edge of the bone. This one extends from about the middle of the rib’s bottom, and it’s longer. It’s more like a thin, curved sliver, a-”

“It looks as if it’s been peeled away from the rest of the bone,” Robb said, “bent back but not enough to break it off.”

“Yes, that’s a good description, that’s what happened.” Gently, Gideon fingered the inch-long sliver. “This cut wasn’t made by the point-well, it may have been started by the point-but, basically, it was made by the blade, which sliced through the thin lower edge of the rib on its way by. Try that on a piece of dry bone, and it would just break off, but when bone is green-that is, living-it’s flexible; it gives, it doesn’t break, and you get a shaving, like this.”

Robb frowned. “But he wouldn’t have died from that either. Or would he?”

“Not from that itself, no. You don’t die from broken bones, let alone nicked bones, no matter how severe. It’s the soft tissue damage associated with it that does you in. And this had plenty of soft tissue damage associated with it. See, to create a slice this wide, the knife would have had to be shoved in pretty far-six or seven inches anyway, assuming it’s shaped anything like a typical kitchen knife-which means that it would have slipped right on through the fourth intercostal space, kept on going through the left superior lobe of lungs, and wound up deep in the left ventricle of the heart.” He put the bone down. “And when that happened, he would most assuredly have lain down and died.”

Clapper nodded. “So we have our cause of death.”

“Well, not for sure. For all we know, he was already dead from some other wound or blow that doesn’t show up on the bones. But there’s not that much difference. If I wanted to use our usual weasel-words, I’d say that trauma of this nature is not compatible with continued life. That would cover it.”

Robb was fascinated with the bone sliver. “Such a little thing,” he murmured. “It’s hardly noticeable.”

“You’d notice it if it was you,” Clapper said, and to Gideon: “Four stab wounds. That’s a lot.”

“Yes, it is,” Gideon said, “especially considering that we have only eight ribs here. There are stab wounds on half of them.”