Android: Free Fall

by William H. Keith

  “Now git!”

  He got.

  I seethed for a moment, and counted to ten. Amateurs!

  His signature had vanished into the plastic box, recorded by the tag’s processors. I added my signature, which would be time-stamped and validated by the tag. It was crucial to keep the chain of evidence well-documented. Otherwise, something vital to the case could be thrown out in court because we hadn’t maintained proper evidence control.

  Alone in the room, I walked over to the desk and carefully set my evidence case on a clean bit of the surface. It didn’t look like the blood had splattered this far. I couldn’t use my thumbprint to open the case, of course, so I spoke to it. “Harrison…Captain…ID 718-2461, Blue-one.”

  Obligingly, the case recognized my voice and hissed open.

  Neatly sardine-packed inside were print goggles, a black light wand, chemical and DNA sniffers, rack upon rack of evidence containers, cameras, microscopes, RIR goggles and scanners, a small DNA analysis computer, and a whole armamentarium of other high-tech gadgets.

  First things first.

  “Crime Scene,” I said, recording my words in my PAD, “Challenger Planetoid, High Frontier Hotel, Room Twelve. Roger Mayhurst Dow, Jr. is the victim.” And I added the case number and the date and time.

  Next I used a microsampler to acquire a measure of blood from one of the semi-liquid puddles on the floor. I took two samples, one to save for the lab later, while the other went into my kit’s portable medical analyzer. The blood, it told me, was Type O positive, the most common of blood types. Roger Dow’s records stated that he was O pos as well. That wasn’t definitive—about thirty-seven percent of all humans are O positive—but it would do as confirmation of the murdered man’s identity for now, until I could get other samples back to a lab for comprehensive DNA testing.

  Turning away so I didn’t accidentally breathe on anything, I thumbed my bubble half open and pressed the RIR goggles over my eyes. In the brief moment that my helmet was open, I caught the sharp, coppery-sweet smell of blood, a smell that had ridden my brain since the War.

  I suppressed my gag reflex, and closed the bubble helmet once more.

  Then I turned back to face the room.

  I knew what to expect, but the anger snapped out again, boiling and insistent. RIR—Residual Infrared—is heat. You can actually track a person in RIR hours after he’s walked across a floor because his footprints are still glowing at infrared wavelengths. In the false-color enhancement of the goggles, the room was filled with the green and yellow haze of residual heat, lots of it vaguely man-sized and shaped, and the floor was covered with glowing, crisscrossing tracks.

  Almost all of those would be from the security team I’d just tossed out, and they’d tracked around so much that there would be no way to sort out their heat traces from those of others—Dow, the maid, or the murderer. I studied the bed; none of them would have been rolling around in that. But blood is hot, and that heat covered the bed, now, saturating it. The blood had cooled, but was still a degree or two warmer than background.

  I removed the goggles and replaced them in the kit. It had been many hours since the murder in any case, and there would be very few thermal traces left by this time. But I wanted to be thorough. I pulled out a UV loupe and put it on before closing my helmet again.

  I used my PAD to call up the image of the crime scene Dawn had given me that morning. The legs had been there, tangled in the sheets. The upper torso had been here, on the floor. An arm had been over here, by the wall. The head—according to the walk-through PAD vid—had been on the other side of the bed.

  The mining laser still lay on the floor, just to one side of the door, as though the murderer had tossed it aside as he’d fled.

  Time to begin looking for prints.

  There are two general classes of fingerprints—patent and latent. Patent prints are like those left by the rent-a-cops on the floor. Someone gets blood on his hand and leaves a visible fingerprint when he touches something. Latent prints are much more subtle, created by the natural skin secretions of a human body; aqueous eccrine secretions, sebaceous oils, urea, even amino acids—they can all be left behind by a touch. They tend to be invisible to the naked eye, but chemistry can bring them out in somewhat spectacular fashion. I used a small squeeze bottle to blow a microscopic puff of fluroninhydrin across the smooth and shiny surface of the laser’s pistol grip. The ninhydrin reacts with the ammonia and secondary amines present in minute traces of urea and other bodily secretions, producing a characteristic blue-violet color called Ruhemann’s purple. The fluorescent component stood out through my UV loupe as a brilliant, blue glow.

  Nothing.

  No prints, anyway. The pistol grip had been smeared, however. Traces of UV fluorescence showed where someone had dragged a swab across the plastic.

  The rent-a-cops, again, damn them.

  There are two ways to process fingerprints but, unfortunately, the two are mutually exclusive, and a crime scene investigator has to make some decisions at the beginning of his investigation about which way he’s going to go. He can develop for prints, which can be photographed, or he can go for chemical and DNA evidence, but not both. The swabs used for chemical evidence destroys prints—as had happened on the laser’s hand grip. And the fluroninhydrin destroys amino acids…and that’s what DNA is made of.

  DNA swabs in sealed evidence tubes were a part of the evidence Daley had handed over to me. I’d have to pray that they’d done a decent job in the collection, and labeled it properly. Ideally, the crime scene is divided in two, with one type of evidence collection on one half, and the other type on the second half. Reality is never that neat, however, especially when investigating a single piece of evidence, like that mining laser.

  I searched other parts of the laser, both for chemical traces and for prints, working in small sections that I recorded vocally, block by block, on my PAD. The yellow jackets had gone over the laser pretty thoroughly already, though. Very carefully, holding it by the tip of its muzzle and the very end of the butt, I turned the laser over to check the other side.

  Damn them. They’d already moved it, going over both sides and destroying any prints.

  I photographed the laser carefully, though, and added notes to my PAD’s crime scene log. The weapon was heavy and bulky, not exactly a precise weapon, and certainly not a neat one. It would have been hard to wield, too—too heavy for most women, unless they were athletic G-mods. Not too heavy for a bioroid, though…or for a gene-modified clone.

  I expanded my search.

  Eventually, I found one partial handprint. It was a patent print—a smear of blood on the wall at the head of the bed. It looked like the outer portion of a palm, plus the tip of a little finger, but it smeared away in a bloody trail. I photographed it carefully at various wavelengths, then stepped back and called up the walk-through on my PAD.

  When you’re collecting evidence at a crime scene, it usually helps to not think about things, to try not to picture what happened. If you do, you’re all too likely to begin formulating a story of exactly what happened in your head…the victim was here…the murderer was there…and if you’re not careful you’ll begin following that story a bit too religiously. You’ll end up looking for evidence that fits your still-forming theory, and ignoring things that argue against it. That is not the scientific method, and it’s a no-good way to find and collect data.

  At the same time, a forensic investigator has to have some imagination, and he needs to have a working theory as he goes in order to figure out what to look for. The only way to balance the two contradictory attitudes is to rein in the imagination and deliberately not form conclusions, even when it’s staring you in the face.

  I took a few steps back and unfolded the big screen on my PAD, calling up the walk-through vid. Zooming in for a close look, I found the smeared handprint on the wall, followed the blood trail down…and there was the victim’s arm and hand in the image, blood-covered and lying on the pi
llow.

  As a working theory, then…the victim had been in bed when the murderer entered. The victim had sat up…maybe bracing himself with one hand against the wall. Sitting up too quickly in four hundredths of a gravity could throw you into the air, so maybe he’d braced himself to keep from becoming airborne.

  The killer fired the laser, shooting wild, and severed the arm just above the elbow. Blood had gushed everywhere, and the hand had left the print as it slid down the wall.

  Not entirely satisfactory, that. There must have been blood on his hand already when Dow had touched the wall. So the first shot had cut him somewhere else, splattering blood. Then he’d braced against the wall, and then the arm had been severed.

  I backed up to the door, sighting through my mental visualization of Dow sitting in bed, one arm against the wall. The laser shot would have left a dark burn track against the wall behind him, which would confirm the location of the murderer when he’d taken the shot.

  Odd. That part of the wall was actually the transplas window behind the bed. I couldn’t find any burn marks there at all.

  Okay…maybe that made sense. Transparent means that light goes through it, and a laser, even a 100-kilowatt mining laser, is just light, after all. But I would have expected some scarring or charring. No transparent material perfectly transmits light, and with a kilowatt laser, if the transplas had absorbed even a tiny fraction of that energy, there should have been some sign.

  I also wondered about the mindset of a person who would fire a mining laser at someone with a window directly behind the target in the line of fire. Unless they were certain the laser light would pass harmlessly through the transplas…would they risk the possibility of puncturing the window and causing a pressure loss that might threaten the entire station? At the very least, with a major atmosphere leak, the automatics would cut in and the room would have been sealed off. All of the rooms at the High Frontier had pressure-seal doors so that an accidental rupture in one wouldn’t vent the atmosphere of the entire facility.

  The murderer would have been locked in as the room air leaked away into vacuum.

  Most of the laser damage I could find was on the bed or on the floor, however, randomly distributed. In fact, it looked like the murderer had been blazing away with indiscriminate abandon—panic-shooting, maybe.

  I took some photos with my PAD, then moved around the room, trying to line up where the murderer had been standing when he’d shot Dow’s arm.

  Nothing seemed to fit.

  One rule of crime scenes, though, is that things rarely are as neat and orderly as you think they should be. There are always factors you’re not anticipating. Good crime scene investigation requires that you discard preconceived notions and concentrate on the evidence. Not until you have all the facts is it safe to begin drawing conclusions.

  I was beginning to have some problems with the crime scene, though. It was overkill to the nth degree. The center of the bed had been savagely slashed again and again; at one point, the mattress was very nearly sliced clean through, the separate edges so clean and sharp they looked like they’d been parted by a fantastically keen razor…or even a monofilament knife. In places the sheets had charred and almost burned.

  Why hadn’t the sheets burned? Mining lasers create fantastically high temperatures.

  Perhaps the blood soaking the sheets had kept them from catching fire. I examined the saturated portions carefully, and began taking samples. In places, the sheets were still soggy; in others, the blood appeared to have dried and even charred.

  Twenty minutes into my examination, I was able to put my finger on what was bothering me most.

  The evidence was not internally consistent.

  I’ve seen a lot of wounds caused by high-energy lasers, both in murder investigations in New Angeles, and before that, during the War. What was bothering me was how damned much blood there was.

  When a laser beam hits human flesh, one of two things can happen. Usually, the beam will slice through skin, muscle, and bone, but because the beam is so hot it cooks the meat as it passes. Blood vessels are sealed off. Proteins are denatured. Tissue chars. There’s very little bleeding.

  This isn’t always the case, of course. If a laser beam hits a body cavity or blood vessel in such a way that internal fluids heat and expand explosively, it can make a hell of a mess. This is especially true of a shot to the abdomen or chest. I remember seeing one poor guy hit in the chest by a combat laser on Mars. It peeled open his pressure suit, his chest cavity exploded, his heart ruptured, and in the near-vacuum of the thin Martian atmosphere almost his entire blood volume—a good six liters—had partially vaporized and splashed across the sand. Not pretty.

  At least he’d died instantly.

  But the way the murderer had been wildly slashing about with the mining laser, I wondered why the wounds hadn’t been cauterized. I took another long, hard look at the walk-through vid on my PAD, trying to picture what had actually happened. Okay…this long, deep slash across the center of the bed was the one that had cut Dow in half just above his hips. That must have released a lot of blood…not to mention the smell that had so worried Fuchida. But I would have expected the shots that had cut off the victim’s arms and head to have cauterized the wounds. In the vid, there was so much blood on the various body parts they looked like raw hamburger.

  Uncooked hamburger.

  I would have to have a look at the body later, or what was left of it. This really wasn’t adding up.

  I didn’t let that bother me too much, though. Wait until you have all the pieces.

  I groaned at my own bad pun, pulled out a microsampler, and began sampling.

  Humans leave traces of themselves everywhere. They can’t help it, unless they’re encased in something like a cleansuit. We’re constantly shedding hair, flakes of dead skin, various oils and secretions, eyelashes, and microscopic bits of ourselves that can reveal a lot when studied in context. The microsampler was a pen-sized vacuum with replaceable, sterile vacuum heads and specimen containers. I pulled some dandruff from a non-blood-soaked corner of a pillow. Some hairs from the sheets and from the floor. I pulled a couple of beauties from the pillows: thirty centimeters long and golden yellow in color. I used a developer spray, then waved the black light wand over everything, using my UV loupe to check for telltale bits of fluorescence.

  I found several patches of something moist on the bed sheets that weren’t blood. One near the edge, two on the bed just outside the saturated part in the middle. All three might have been contaminated by blood—hell, there was blood everywhere on the bed, from stray droplets to complete saturation—but my club’s chemical analysis should be able to separate that out.

  And then…hello! What’s this?

  A fingerprint…a perfect fingerprint, invisible until I dusted it with a powder form of DFO. It was located on the bed frame, up near the head. DFO—formally 1,8-Diazafluoren-9-one—reacts with amino acids, and can pick fingerprints out of porous materials like paper or bed sheets as well as from less permeable materials. After dusting, I passed a blue-green light stick emitting at 470 nanometers above that part of the frame, and got a strong excitation emission at 570 nm.

  I used a hand microscope to study the print…then to photograph it. I swear it was perfect, no movement, no smearing at all…

  And yet there were no ridges, loops, or whorls.

  Nothing.

  I was looking at the fingerprint left by a bioroid.

  All humans have fingerprints, of course, tiny friction ridges in the epidermis, and no two humans have the same prints. Even clones, perfect genetic copies of one another, have different fingerprints. Identical twins—and clones are biologically nothing more than identical human twins—have different prints, because fingerprints have more to do with position, contact, and blood flow in the womb than they do with genetics.

  So a bioroid had been in Dow’s room.

  Not only that, I knew the bioroid had been there recently…say, within
twenty-four hours. Why? A little-known fact about fingerprints is that children’s latent prints tend to disappear after a very few hours. That’s because their skin lacks the waxy oils that become so prominent at puberty—think of adolescents and their acne breakouts. The fatty acids and sebaceous oils in younger children are much lighter, and tend to evaporate rapidly.

  The same is true of the oils associated with a bioroid’s artificial skin, though to a lesser degree than with kids. They’re present, certainly, to keep the skin supple and lifelike, but they’re water-based and don’t hang around for more than a few hours.

  And why did I pick up that latent print with a chemical that reacted with human amino acids? Easy. We tend to collect an awful lot of junk on our fingertips just in the day-to-day process of living. Ordinary fingerprints, for instance, carry a lot of heavy sebaceous oils even though the glands producing those oils are not present on the fingertips. Why? Because most of us have the lifelong habit of unconsciously touching our faces or our hair, of rubbing our foreheads or scratching our scalps…and those are places that have a lot of sebaceous glands secreting heavy skin oils or, in the case of hair, of collecting it. The oil builds up on the fingertips, and then is left behind in a latent print.

  Bioroids have no amino acids in their chemical make-up, of course. If a bioroid had left amino acids in a fingerprint on the bed, it could only be because it had touched human skin first, exactly like a human picking up sebaceous oils from the face or hair by touching them. Amino acids are water-soluble, and would be present in the moisture of the print, though in very tiny amounts.

  I was beginning to get a very interesting picture about what had been going on in that room. The position of that one fingerprint on the bed frame alone suggested the ’roid had been in an odd position…and that suggested that Dow’s visitor had been a playmate. And there were those long, blond hairs on the pillows.

  The elevator mercs appeared to have missed the bed frame, so I dusted the rest of that side, looking for latent prints, and used swabs to collect possible oils and residues from the frame on the other side. I photographed everything, and recorded locations and impressions on the evidence tags. I was already acquiring quite a large collection. I moved carefully, recording each part of the room before I entered it, though the way those clowns had tracked things up already I scarcely needed to bother.