I’D ARRANGED TO MEET Art at KPD headquarters at 7:30 A.M.: just before his undercover shift at Broadway Jewelry & Loan began; just before he waded into the sewers of cyberspace, trolling for the creeps who troll for kids, pursuing the monsters who peddle kids. Art was waiting just inside the glassed-in lobby of the building; he took the plastic jar—now containing both the skin and the solution that had rehydrated it—and inspected it, nodding in approval or optimism. We took the elevator up to his lab and he set the jar on a tabletop, then donned a pair of snug latex gloves.
Unscrewing the lid, he extracted the skin with a pair of tweezers, then unfurled it slowly on a tray lined with paper toweling, studying each fingertip in turn, gently blotting it dry. Finally he spoke. “All of the fingers are torn in places, so we won’t get any prints that are completely intact. The center of the fingertips are intact, though, so I’m pretty sure we can get enough details for a match, if this guy’s prints are in aphids.”
“Aphids,” I asked, “like the rosebush-eating garden insect?”
“No, Dilbert,” he said. “AY-fiss, A-F-I-S, like Automated Fingerprint Identification System.” He frowned, then corrected himself. “I mean I-AFIS. They tacked an I on the front end a while back—stands for ‘Integrated’—but I still call it AFIS. Force of habit.”
“Easier to say ‘AY-fiss’ than ‘EYE-ay-fiss,’ too,” I said. “Especially for an old dog like you.”
I remembered that AFIS was a database created by the FBI six or eight years earlier. Before its creation, I could recall Art squawking about the weeks or even months it took the Bureau’s fingerprint lab to analyze prints. The delays often meant that by the time a match was found, a suspect who had been arrested or detained for questioning was no longer in custody—and nowhere to be found. These days, he told me, it was possible to get a match—a name—within two hours in criminal cases, and within twenty-four hours for civilian requests such as employment background checks.
“How big is their database by now?” I asked.
“Pretty darn big. Last time I looked, they had prints from nearly fifty million people on file.”
“That is big. I didn’t realize so many of our friends and neighbors were criminals.”
“They’re not. Remember, a big chunk of those are people required to submit fingerprints as part of their employment—teachers, military personnel, firefighters, gun buyers, all sorts of folks. Mine are in there; yours probably are, too, aren’t they?” He was right, I realized. When the director of the Tennessee Bureau of Investigation had asked me to serve as a TBI consultant, I had filled out a long questionnaire and had been fingerprinted, presumably to make sure the agency wasn’t hiring a fox to help guard the hen house.
As I watched in fascination, Art carefully fitted the dead man’s skin to his own right hand, then walked to a laptop computer sitting at the end of the table. Beside it was a thin rectangular gadget, slightly smaller than the laptop’s keyboard, with a blue pad on top. Using his left thumb and forefinger to stretch the skin taut over his right thumb, he laid one edge of his thumb on the blue pad and rolled it in a half revolution, from one edge of the nail to the other. After a few seconds, a six-inch-high swirl of tightly nested lines appeared on the laptop’s screen.
“Hey, where’s the roller, the ink, the glass plate?” I asked.
“Bill, Bill,” he said. “Ink-on-slab is so last-century. This is optical scanning. No fuss, no muss. Digitizes the prints directly, and lets us upload them directly to AFIS. We can print out hard copies on standard fingerprint cards so Jess and the Chattanooga PD can add them to their files, but this is a lot quicker and easier than the old way. Shoot, the new criminalists we hire these days, kids fresh out of school? Some of them have never rolled a set of prints in ink. Or if they have, it was just as a history lesson, a demonstration of how things were done back in the day. Like letting kids milk a cow or churn butter by hand to show them the pioneer way.”
“You sound disgruntled,” I said, “but I notice you’ve switched over.”
“Hard to argue with results,” he said. “Hey, do me a favor, since I’m using both hands? Come hit ENTER on the keyboard there, to accept the print and let me get the next one.”
I did, for the thumbprint and each of the four fingerprints. Once he had finished scanning the prints, Art returned the skin to the jar, screwed the lid on snugly, and handed it back to me. Then he peeled off his gloves and tossed them in a container labeled BIOHAZARD. He went back to the laptop and clattered the keys for a few minutes, then hit the ENTER button with a flourish. “Okay, they’re sent,” he said. “We should have an answer within a couple hours.”
“How can it be so quick? You said there are nearly fifty million sets of prints in the database, right? That’s nearly five hundred million fingertips to compare.”
“I guess the software’s pretty powerful, and their mainframe has a lot more horse power than our little personal computers,” he said. “I mean, it’s easy to narrow it down.” He hit a few more keystrokes, and the thumbprint reappeared on the screen. “Prints have one of three basic patterns,” he explained, “whorl, loop, and arch. Whorls are concentric circles—like a target with a bull’s-eye at the center, or the cross section of an onion. A loop pattern is more complicated; the ridges come in from one side, make a U-turn, and go back out the same side. In an arch pattern, the ridges come in from one side, go up in the middle, and then go out the other side.”
I studied the pattern on the screen. “So our guy has a whorl pattern,” I said. “At least on his thumb.”
“Bingo,” said Art. “So when the AFIS software is looking for a match for this particular print, it searches only right-hand thumbprints, and only those with whorls. That means it only needs to compare this print with, I dunno, maybe twenty million others. Still a lot, but there are other criteria and features that can progressively narrow that down tighter and tighter.” He pointed to two areas on the print where the circular pattern of ridges gave way to a triangular intersection, as if the whorl had been shoehorned into an arch pattern. “See those? Those are called deltas. Pretty easy to tell if the deltas on one print are spaced differently from the deltas on another. I’m not a software guy, but I imagine it would be fairly straightforward to program a computer to recognize features like deltas and compare their locations on an X-Y coordinate system.”
Art promised to let me know later in the day if AFIS returned any hits on the prints. “I can’t access AFIS from the computers at the pawnshop,” he said, “but I’ll dash over here at lunchtime and see if we got lucky.”
He rode down the elevator with me and we walked out into the crisp morning sunshine. I was headed to UT to teach Tennessee’s brightest and best. He was headed to Broadway Jewelry & Loan to stalk Tennessee’s darkest and worst. “Thanks, Art,” I said. He nodded and headed for his car. “Hey,” I called after him. “Go get ’em, Tiffany.” Without looking back, he raised one hand in a parting wave. His middle finger was extended. The gesture was aimed not at me, I knew, but at the men who were his quarry. The predators out there lurking in cyberspace, waiting to pounce.