Not that we knew any of that at the time, of course. We were engaged in the endgame of a three-month sting operation that would, if we could pull it off, eliminate at least a quarter of organised crime in New York - and secure us virtually unlimited State funding for the foreseeable future. The Commissioner, Ed Callaghan, made it very clear how much was riding on this op...as if we didn't already know.

Sergeant Candy White had already made an enormous personal sacrifice in the process of setting up the sting: she'd volunteered to assume the role of a high-class prostitute to infiltrate the Cartel, as they called themselves. Except she wasn't just playing a role; she actually was a prostitute (though she received inoculation against every known STI and a contraceptive implant), turning tricks with the best - or worst - of them. She'd even been arrested - twice, which merely added to the artistic perfection of her cover - and treated just like any other prostitute. Mind you, she was arrested not by Unit officers but by the regular NYPD Blues, who had absolutely no idea she was a sting agent of ours.

And we weren't so stupid or careless as to tell them, of course!

Her performance would later be presented for study at the Police Academy as an example to other would-be infiltrators, showing just what could be achieved with sufficient drive, determination and dedication to duty. Candy herself was decorated and later promoted in recognition of the tremendous personal risk she'd taken. More than once she fell afoul of abusive clients, one of whom actually tried to kill her for his own sadistic and sexual pleasure; he turned out to be a deranged misogynist who wanted to gut a woman and watch her die slowly and in agony. But he made two mistakes which proved to be his undoing. First, he actually told her what he planned to do, hoping to evoke fear and thus increase his own kick.

Though she admitted in her post-op briefing that he had scared her, and she'd deliberately let her fear show so as to deceive and distract him, she certainly didn't succumb to panic as a less well-trained officer - or an untrained civilian - might have. "Well," she protested indignantly, "facing someone who's just told you he wants to kill you is scary!"

Second, far more crucially, he badly underestimated her. That was understandable, as she was petite and slightly built, looking as if she would blow away on a stiff breeze. She had, however, counted upon this error, and she certainly didn't look as if she held a Black Belt, Fifth Dan, in judo.

But she does. I've seen her in the dojo tossing hulking bruisers twice her weight or more through the air as if they were featherweights, and she has a way of planting herself like the sturdiest oak tree - when she does that, those same hulks find her utterly immovable. I don't know how she does it. She trains most of our rookies in hand-to-hand, and she trains them hard. The only opponent of hers I've ever seen leaving the dojo without at least bruises is her sensei, and she can even give him a hard time.

As for our would-be murderer, Candy gave him the worst good night of his life. She let him get close enough to stab her...except she was suddenly no longer there, because she'd leapt up into the air, somersaulted over his head, landed behind him - and delivered a nerve punch that harmed him not in the slightest but instantly paralysed him, shades of Serenity's Operative. She whipped off his jacket and bound him with it, then called the police. As the Blues were hauling him off, she whispered menacingly in his ear:

"You wanted to kill me? Enjoy my pain, my death? You. Wish. I could've killed you. For what you tried to do to me, believe me...I wanted to. I know ten different ways with nothing but my hands. Just remember that, pervert. I could have killed you."

Okay. Hands up anyone who can blame her for her anger.

What?! Get outa here!

Anyway, back to the op. Some $50million worth of drugs and the same amount in diamonds - all genuine and all genuinely stolen by our deep-cover officers, to add verisimilitude to the sting (to be returned later) - were about to change hands. Of course, the moment they did the perps would unknowingly prove their guilt, as Candy would be there - with a microminiature HD camera in her eye recording every detail and transmitting in real time to our boys and girls. Yes, she volunteered for that, too; such equipment is not standard Unit issue. We'd rather not violate privacy laws if we can help it.

(With the exception of Jocelyn Barton, who gets a kick out of covertly filming couples having sex - including herself - but she's got a whole sheaf of issues, believe me; she's regularly seen naked in the co-ed changing rooms, utterly unashamed and unembarrassed. There's been many a male rookie who didn't know where to look, poor lads. Hell, she once changed her tampon right in front of a lad who, that very day, had just graduated from the Academy and, I'm pretty sure, had never even seen a naked woman before - and he was so young and naïve he surely had no idea what she was doing or why there was blood everywhere!

To be honest, if it weren't for her exceptional skills in forensics IA would've insisted upon her removal (if not criminal charges) long since. She's a kinky bitch on her own time and occasionally on Unit time as well, but on duty she's a damn good officer, utterly professional while being a fast and accurate worker who submits concise yet highly detailed reports. What can you do?)

We'd cased the entire building well in advance, disguised as an OSHA team performing a routine check to verify the structure was up to code. To add verisimilitude to our cover we even issued a minor citation to the building's owner, on account of the ventilation system's filters being not quite up to standard, but the structure itself passed (and it really did; we have OSHA training, too - comes in handy as cover for ops like this one).

What we really did, of course, was:

Check and verify all entrances and exits, concealed or not;

Determine any structural weak points in case we were forced to use artillery at any point;

Establish and map any and all possible lines of fire (theirs or ours);

Map the electrical and communications infrastructure so we could subvert it at need.

We were ready fully two days before the Cartel bosses were due to meet with their Russian counterparts to seal the deal. One complication was that we'd found out the Russians were planning to bring some...entertainment...with them to celebrate the closing of the deal: six whores, two of whom were believed to be underage. Thus Candy's primary mission, once we moved in to make arrests, was to make sure those girls, who were technically innocent bystanders, got out safely if everything fell apart.

Even if she had to risk her own life to do it.

But she didn't even blink when I told her. She told me soberly, "Sir, my younger sister - she's three years younger than me - was forced into prostitution for a short while by a perv teacher when she was twelve. I swore I'd die before I'd let that happen to any other girl; I couldn't do much about it then, but I sure as hell can now. I'm in, sir, I'll get it done."

She's a real trooper, so brave. We're all proud of her.

So. We had one team overlooking the roof from an adjacent building, another on the floor below the meeting room (inserted over 24 hours previously), a third covering all ground floor exits. All were non-lethally armed, all had motion trackers - and all had field medkits, just in case. But we didn't expect to need them. Morale was high; we were sure this was in the bag. The perps didn't suspect a damn thing. We had total visual surveillance in place, complete coverage. What could go wrong?

Yeah, right.

The Hunter noticed something interesting happening at the tall building. Oomans, carrying armament and other equipment, were gathering in tight teams around, on and in it. He took a moment to admire the discipline and precision of their deployment; Swift Kill was right, he saw - the oomans understood warfare full well. It seemed a battle of some sort was imminent. He briefly debated which side to attack.

But no, the choice was obvious: the ones inside would be the greater challenge. He'd heard close-quarters combat was something oomans excelled at.

So did the yautja.

His choice made, he leapt onto the roof, landed gracefully in this lighter gravity - and froze.

The mask sensors had detected a scan of some sort. He held his position, utterly motionless, confident in the capabilities of the rhh-kosh.

And, of course, in his own skill and Swift Kill's training.

The next move is theirs, he decided. I shall wait.

From my vantage point one building over, I began polling the teams. "Team One, report," I requested softly.

"In position," Duane Holmes answered from inside, "all clear, Commander."

"Two?" That was the exit cover team.

"Clear, sir," Jerry Hamilton reported.

I allowed myself a grin. This was going like clockwork. "Base, you getting Candy's feed?"

"That's a big ten-six, sir," Operator Frankie Sandford replied impishly. She was barely 20, way too young to remember the days of trucker slang, which explained her mistake.

"That's ten-four, you doofus," I chuckled.

"Whatevs," she sighed.

"Three?" The rooftop team.

Team Three Leader Denny Murphy started to say "Clear," but he only got as far as "Cl -" before a soft beep from the Siemens Mk. 5 Motion Tracker attracted his attention. He scrutinised the screen, but could see nothing...except for a weird shimmer of some sort. He wiped sweat from his brow - damn, it's hot tonight - and squinted, but it didn't make the whatever-it-was any clearer. "Sir, I've got...somethin'...can't make it out. But I read in Cop Tech that Siemens MT scanners sometimes go skiddy in hot air and, Christ, it's hot tonight," he finished with feeling.

I wasn't in any mood to take chances - either with my teams' lives or the success of the op. You'll note the order of priorities there. "All teams hold," I ordered. "Team Three, report!"

He remained motionless. The oomans were still scanning, though not for him, he was sure. They had no idea yet he was here (though that would soon change, he mused with relish); the yos'fel-esh was too small, too swift and of the wrong materials to have been detected by the scanners known to be used by their military in protecting their world...they hoped. Well, possibly they might have gotten a momentary scan, no more, but it would've appeared to be a meteorite to any ooman who might have seen it, and they were surely accustomed to seeing those.

A Hunter's greatest weapon is patience, Swift Kill told him once when he was but a stripling, at the beginning of his training. It took him a long time to understand, but in the end he did. A patient Hunter was a successful Hunter.

There was no rush. He would wait.

Denny adjusted the tracker and ran a quick and dirty diagnostic, finally resorting to the tried-and-trusted method of whacking it.

The shimmer vanished.

(Only because Young Blood had noted the brief cessation of the scan whilst the diagnostic was running - a software flaw, rare for Siemens, and another reason why the Mk. 5 was denigrated in the Cop Tech article - instantly seized his opportunity and swung himself over the lip of the roof, though we only figured this out some time later.)

He breathed a sigh of relief and answered, "Clear, sir. I think it was a glitch."

I made my decision. "Team One: GO!"

He saw one armed ooman apparently standing guard. That one would be first. He primed the okh-ist, the burner. The targeting beams focused, and the mask confirmed: target acquired.

He fired.

The tightly contained plasma bolt ripped straight through Dmitri Gusev, instantly ending his life, and hit a gas pipe. There was a tremendous explosion.

I started in shock. What the fuck -?! "Team One!"

"That wasn't us, sir!" Holmes yelled. "Somethin's goin' down inside!"

Inside...? Oh, God, Candy...! "Base, pull Candy out! NOW! Team One: HOLD! Do NOT enter!"

"Copy that, sir, holding position! Christ, what's goin' on in there?!"

Even over Holmes' transceiver we could hear screams.

That was unplanned, the Hunter cursed, but then he realised the opportunity for confusion it offered. With a Hunter's instinct, he knew the time to strike was NOW!

None of the men and women inside were remotely prepared for the invisible nightmare which burst into the room. Abruptly there seemed to be blood and falling, mutilated bodies everywhere. Automatic weapons were roaring, spent shell casings falling like rain.

More literal rain was falling, too, but it wasn't just water.

Candy White was no stranger to blood and guts, and she'd killed in the line of duty - and had suffered injuries - more than once. But being showered with a woman's blood and brain matter as the top of Ivana Tereshkova's skull split open was more than even she could take. Horrified, she screamed in bone-deep revulsion and terror and utterly abandoned her mission, her fight-or-flight survival reflex taking total control. But as she tried to flee, she ran headlong into -

- nothing.

But there was something there. Something blurry, sonething moving.

Something killing.

Instinct kicked in again, and she lashed out.

He barely registered the blow as he ran an ooman through; it shrieked and died, eviscerated. This ooman was tiny even by their stunted standards, surely no warrior at all. Yet it was brave, to strike out unarmed at yautja. By rights he should have killed it for its temerity. But the Code was clear. So he defended himself honourably: a gentle backhand would suffice.

Of course, "gentle" by yautja standards was more like "piledriver" by human measures. The blow lifted Candy off her feet and she flew, instantly unconscious, to crash to a halt under a table. No-one took any notice. They were too busy: either engaged in fleeing, as the whores were doing, trying futilely to defend themselves - or, in Young Blood's case, having the time of his life. Kill after kill he claimed, impaling here, decapitating there. The oomans were putting up a valiant defence like the cornered animals they were - but they were no match for him!

This is LIFE! he roared in his mind, exultant in the glory of the honourable kill.

Soon all the armed oomans were dead. He rapidly and efficiently took his trophies. One ooman, he was pleased to note, had drawn a bladed weapon and had wielded it with skill. He'd seen such a blade before, a weapon trophy from the Blue World taken some ten hands of seasons ago. That long, slim blade with the long two-handed grip was known to be wielded only by the very best ooman warriors; the ooman name for it was almost yautja in its sound: k't'nhah, or something like that.

Thus, as was the yautja custom, he paid particular tribute to that one by ripping out its spinal column and skull in one piece.

The manner of the female's death gave him brief pause for thought. Certainly she was a magnificent specimen, taller than some of the males who were not short, by ooman standards. But she had tried to fully deflect his decapitating strike with her weapon, failed, and the partly-deflected blow had resulted in the ruination of her skull. Yet tribute and respect had to be paid; she'd used the weapon as a club and not a firearm - an act of instinct, bravery or both.

She was strong; had the weapon been a little tougher or heavier her tactic might have worked. A good try, he decided, and so he took the permitted alternative trophy when dealing with female oomans: her kh'hli, the bone cradle of her legs and birthing sac.

Then his keen hearing picked up more oomans approaching and the mask scan confirmed it. They would be forewarned, he knew, and thus the odds were now against him (he wasn't to know, of course, that these oomans carried only non-lethal weapons...a concept almost beyond the comprehension of the yautja, a contradiction in terms to their way of thinking). A Hunter dying gloriously was still a Hunter dead...and the Hunt was nowhere near completed.

There would be another time.

He leapt for the hole he'd made in the ceiling and made good his escape. No ooman saw him. That was as it should be.

"In position outside," Holmes whispered tensely. "Can't hear movement. Nothing registering on tracker."

"On my command, Team One," I ordered quietly. "Teams Two and Three, hold your positions. MedEvac en route, ETA three minutes minus. Base, how's Candy?"

Back at Base, Frankie queried the monitor system frantically, fearing the worst because Candy hadn't reported in once whatever had happened had kicked in. But to her relief Candy's life signs were coming through, relayed via the implanted eye camera. "She's okay, sir. I think she's unconscious, diagnostics report possible concussion, but she's alive, thank God."

At that we all breathed a sigh of relief. Candy was no kid, but somehow everyone in the Unit saw her as its baby, or its mascot. "Team One, IR readings?"

I could practically hear Holmes' puzzled frown. "We read nine, sir...one normal temp, eight coolin' off." Corpses, we knew. The warm body was, thankfully, Candy.

Wait...including Candy, we'd clocked sixteen going in. The six whores had managed to escape, Team Two efficiently pulling them in and securing them. That left ten including Candy. So who and where was the other one? More to the point, what happened to the others?

Who blew our meticulously crafted op into orbit?!

"Get in there!"

They did.

It took us all a long, long time to forget the first image we received from Holmes' helmet cam. I've seen slaughterhouses with less blood.

There was a man who'd been sliced in two at waist level. A statuesque woman I recognised (from what was left of her face) as Ivana Tereshkova, a Vladivostok assassin and bodyguard for hire, was missing part of the top half of her skull...we later identified the brain matter poor Candy was coated with as belonging to Tereshkova.

I tried not to vomit as I noticed her lower half was also soaked in blood, her legs detached and her sexual organs ruined...we later discovered that, bizarrely, her entire pelvis was gone.

One, still holding his katana, was lacking his skull and spinal column. Jesus. He looked like Hirata Tomosawa, a Japanese gun for hire.

The only bodies present were those of the perps, so whoever hit them had gotten clean away.

There had to be more than a thousand shell cases strewn about the floor, and every wall had multiple bullet holes. Curtains were ablaze from the explosion, which had apparently come from a gas pipe, but Team One efficiently extinguished the fire. And under a table, off to one side -

"Candy!" several team members cried simultaneously. Holmes raced to her, skidding to a halt on his knees, but as per standard practice, drilled relentlessly into each and every Unit member, he did not try to move her. Gladys McCann, the forty-year veteran EMT who'd trained the Unit, had always emphasised that:

"Do NOT, EVER, move an injured person until qualified medical help arrives," she'd sternly warned us. "There are many medical problems which can be exacerbated by incorrect movement. I once saw someone with what should've been a minor, treatable neck injury...but some idiot moved him just the wrong way, his neck broke, and he is now, needlessly, DEAD. There are ways in which it should be done and other ways it should not. Sometimes, yes, you've got to move someone to remove them from greater danger, but even then there's a right way and a wrong way to do it."

So Holmes, entirely correctly, examined her by touch alone - that, plus the latest doohickey from Siemens Electronics, our preferred supplier: the Life Readings Scanner, our 21st Century answer to Star Trek's tricorder. "No injuries other than facial bruising and mild concussion, Commander; we can move her."

"Okay, standard drill - seal the building, get Forensics in there, get those girls back to Base." I let out a breath I hadn't realised I was holding. "Especially Candy."

New York Tactical Operations Unit Base, Manhattan

Two hours later

I called each Team Leader and a shaken but recovering Candy to my office for debriefing - before the Commissioner could get at them. Communications were locked down to Unit standards...that is to say, no-one outside of the NSA would hear one single word, and even they would have trouble. I sighed. "Okay. This op somehow turned into a grade-A clusterfuck, and we all need to know how. Any minute now I'll have the Commissioner breathing down my neck, so before that..." I sighed again, "Duane, I'll start with you."

Holmes shook his head. "No-one came past us, sir. We were clear," he insisted. "In fact I'm not even sure how they got out."

Jerry reported, "The only people we saw were those girls, sir; we grabbed them as soon as they ran out. God, they were terrified, sir - and they were all blood-spattered." He too shook his head. "Our intel was only partly right, Commander; all those whores were underage - not a one was older than sixteen."

"Child Services?"

He nodded. "On it, sir."

So now we'd come to a more crucial witness, namely Denny. If, as it appeared, he'd missed something, he would surely catch hell from Ed, and I didn't want to see that happen. So I gave the kid a moment before asking, "Denny?"

I've seldom seen someone look so tortured. He was clearly thinking the same thing. But he met my gaze and said quietly, "Commander, I'm honestly not sure what I saw. I thought it was just a heat shimmer at first; when we got back I looked up the Mk. 5 MT in Cop Tech, and I was right - they're not 100% in hot air. It was the Feb '27 issue," he added, trying not to sound as if he was covering for himself.

But I recalled reading the same article (Ten MT Scanners Compared - Which Does Your Department Use?), and he was right; the Siemens Mk. 5 was rated only third best out of the ten, and given that we'd had a prediction for a hot summer I had in fact requested the later model, the Mk. 6. We hadn't received them yet. "So what was wrong with it?"

"Well, that's just it, sir: nothing. As soon as we got back to Base I ran a full diagnostic, but it checked out. Then I uploaded its imagery and ran it through correction software...but it still showed that shimmer. So whatever it was, that was what the camera actually saw." He started to warm to his theme, as these tech-savvy kids tend to do. "I analysed the shimmer using 3-D real-time ray-tracing, and it showed that what we're seeing -"

He showed us the original and corrected image side by side on his tablet screen. As far as I could see, they were identical.

"- is what was behind whatever - or whoever - that was; in other words, we saw what we would have seen if there were nothing there at all!" He brought up a third image with the shimmer removed; it was almost the same as the first two.

"You mean it bent light around it?" I inquired incredulously.

"In real time?!" Jerry gasped. "No way possible!"

"Possible," Denny disagreed, "but it'd take so much CPU power and ultra-fast SSD RAM there's no way you'd fit it into anything portable. And I don't have the first clue as to how you'd project it onto such a complex irregular body as a person, or how to project it so you get the same effect regardless of viewing angle."

Candy spoke for the first time. "That's serious tech, sir, way above street or even gang level."

"Yeah, more like military," Holmes agreed pensively. "It's a stealth screen."

I could see where he was going with that, namely suggesting it as a get-out clause, but I liked it. "And not something we could realistically have counted on," I finished the thought. "Seems we've got a new player in town - and he's a major-league pro." I turned now to our most crucial witness. "Candy, are you okay for this?"

She nodded like the trooper she was. "Yes, sir."

"Okay, tell us what you saw, Sergeant."

Candy frowned. "I'm not sure. All I could see was that shimmer in the air - and...and those people, coming...apart...!" She shuddered with the horrible memory, but forced herself to go on. "But then Tereshkova bought it, and - oh, God, it was horrible...her forehead just burst apart and I got spattered..." She sighed. "I regret to inform you, sir, that at that point I'm afraid I totally lost it. All I could think about was getting out alive.

"But I ran into - something. I couldn't see anything, but I lashed out, I think instinctively. Then something hit me, and that's all I can remember until I woke up at Base, sir." She sighed. "I'm sorry, Commander, but that's really all I've got."

"That's okay," I told her gently, "you went through a hell of a lot for this op, and not just tonight. Go home and get some rest, you've earned it. That's an order," I added sternly to forestall the inevitable protest, stemming from her sense of duty, that she was fine and she could manage. "Stop off at Denny's lab and upload your eye camera footage. We'll arrange to remove the implant in a day or two."

"Yes, sir," she surrendered good-naturedly. She rose, as did Denny, and they left the office. All Denny had to do was open a secure wireless channel on a PC or tablet, and Candy would need to blink her left eye in a specific sequence; the upload would be automatic, nothing messy or complex such as in SF, the 007 movies or Gerry Anderson's obscure Doppelgänger.

There was silence. Finally Holmes broke it. "So what do we tell Ed?"

"We don't tell him shit," I sighed, "I'll tell him...something. When I figure it out. First, though, I'll see what Jocelyn has. You guys submit your reports, then get outa here. You've done all you can for now."

They complied, but halfway through the doorway Jerry hesitated as I'd half expected him to. "Sir...did we fuck up tonight?"

I debated dismissing his concern, but my own self-honesty wouldn't let me. "I don't know, Jerry," I admitted, "I really don't know."

Next stop: Forensics Lab, and our resident perv. I grimaced at the thought. I'd never liked Jocelyn even before her kinky tendencies came to light, and Candy for one actually despised her. What she thought of us, neither of us had ever dared ask. However, if there were to be any answers to be had re our mysterious assailant, the data would show up in the bodies and/or samples, and Jocelyn would do her usual impeccable job of processing them to generate information.

Didn't make her any easier to work with, though.

Forensics Lab

Arms bloody to the elbows as she worked on Tomosawa's corpse, Jocelyn acknowledged my arrival with a typical offhand comment: "Hmm. Wondered when you'd get here."

"Stow it, bitch, I am not in the mood," I growled irritably. "The entire future of the Unit - starting with the question of whether it even has a future now - may depend on what you've got."

"Yeah, I heard it didn't go well," she murmured, gazing intently at a tiny piece of spinal tissue.

That did it. I really had had enough of her 'tude! "If by 'it didn't go well' you mean 'some tech ninja vigilante prick utterly fucked up a three-month sting op and cost us about two million, plus we'll never get to try the perps 'cause they're all fucking DEAD', then NO, it DIDN'T go well!" I roared.

Her reaction to this was entirely unexpected. She looked up, actually managed to look contrite and quietly said, "I'm sorry, sir. I had no idea things were that bad."

That gave me pause for thought. It wasn't like her to display such a correct attitude so readily. That meant she'd found something out of the ordinary...not that anything was 'ordinary' about this case any more. I really did need something concrete, and there was no point in antagonising her. So I also apologised and asked her what she'd come up with.

Jocelyn sighed. "Well, to be honest I'm not doing any better than anyone else, it seems. We have eight stiffs where we should have nine, for a start; the amount of blood at the scene was approximately 112.5% of what you'd expect from seven adult males and one adult female who have been virtually exsanguinated, i.e. nine-eighths as much. I have nine, not eight, distinct DNA traces from the bodies." Now she grinned in the way I more expected. "One guy had traces from two other guys on his dick, so he was - unsafely - fucking Mr. Missing and Tomosawa here," she gestured towards the cadaver on the table.

"COD?" I inquired.

She sighed again. "This is the part you are not gonna believe. The perps we have? All dead from blade wounds, inflicted with a combination of precision I'd expect from a surgeon and sheer force I'd expect from a butcher. Except Dmitri Gusev," she added, glancing at one cadaver set apart from the others, "who was presented with a serious breathing problem when he got a hole blown through his chest I could put my head through if I were so inclined to be weird."

(That's rich coming from you, Jocelyn, I mused silently and wryly.)

"I have no idea how it was done; it looks as if he took an artillery shell, but the wound's fused, cauterised - no powder burns, no shrapnel. I've never seen or even heard of anything remotely like it. From the entry and exit angle, I'm pretty sure whatever did it also set off the gas explosion."

If this came from anyone but Jocelyn Barton I wouldn't have believed it. But still...

"Blade wounds?!" I gasped. "The perps had automatic weapons and were firing at close range...and you're telling me our ninja took them out with a blade?!"

"Not only that, but...they entirely missed him," she went on. "I'm discounting the possibility that the ninth blood trace belongs to the attacker for the simple reason that the amount corresponds roughly to an adult's total blood volume. So if he was hit and he bled out that much, he would now be dead, and therefore here. Since he is not, I conclude that they all, somehow...missed him completely."

I forced myself to look at Tomosawa. He'd been sliced down either side of his spine, the cuts starting (so Jocelyn said) from his scalp, slicing deep into his neck and body. "How many cuts?"

"Three," she answered, to my further shock. "One, the killing blow, cleaved his heart in two. The killer then made just two continuous cuts, then ripped out his spinal column and skull - in one go, as far as I can tell. Incredible." She shook her head. "It seems impossible that such accurate killing cuts could be inflicted with such force, or conversely that such forceful cuts could be made so precisely. Yet all the evidence points to just one conclusion:

"Every one of the blade victims died from one, and only one, wound, inflicted with a combination of incredible precision and lethal force."

"But the one precludes the other," I objected.

"True normally, but somehow this guy can pull it off."

"How much force?" I wondered.

Her reply startled me all over again. "Enough to kill just from blunt force trauma, actually. The actual cuts were little more than the coup de grâce."

I couldn't help my shocked gape at her.

"Plus certain bodies aren't complete. One's missing his head, sliced off precisely between the third and fourth vertebrae; Tomosawa, well, you can see for yourself; and Tereshkova is missing her entire pelvis - removed with, again, incredible precision and a minimum of cutting. The one exception to the precision of death cuts was Tereshkova, but that's only because she managed to partly parry the cut with her AK-47...'partly' being the operative word. But all she succeeded in doing was to turn a clean decapitation into an upward diagonal cut through her forehead, which," she added with gallows humour, "is how Candy ended up wearing most of her brain.

"The AK-47 was practically cut in two. Her entrails and genitalia were found discarded below the killer's point of entry and egress: a hole in the ceiling. No DNA traces recovered from the hole except hers. No DNA at all in that room except from our eight guests here, the missing corpse, Candy and the six child whores.

"Every round discharged was fired by the perps. Ballistics match perfectly with the weapons we found. No weapons unaccounted for." Jocelyn sighed a third time. "But now it gets worse, if you can imagine such a thing. I can't ID the blade's alloy; there are no metallic traces in the wounds - none whatsoever, not even where the killer sliced through bone."

"That's impossible," I immediately returned, "any blade, however sharp, always leaves traces owing to interatomic friction and van der Waals forces. They can be detected by SEM-WDS, and I'm sure I read in some issue of Cop Tech that the technique's been refined lately."

"Hmm, you certainly paid attention on the Physics course," Jocelyn noted approvingly. "And you're right; it was the -"

"- May '26 issue," we said together, as I remembered the Terror Twins - and how we'd finally nailed those evil bitches.

While I was still a detective in the NYPD, the year before Ed helped to create the Unit, a pair of identical twins took it into their heads to start killing people for fun - and when I say 'identical' I am being absolutely literal. The embryo from which they grew must've split so early that it divided exactly down the middle; each was the functional clone of the other, their DNA identical virtually to the last gene. Normally there would be hundreds of differences, but not in this case.

Which made it impossible to pin DNA evidence on either one of them, because one twin would commit the crime whilst the other, posing as her, made sure she could be seen in public - witnesses, plus CCTV. It was impossible to definitively state that Susie Kingston knifed Manisha Choudhury to death near Van Cortlandt Park when dozens of people saw her dancing half-naked on a table in Chico's Bar on 79th St. at the exact same time. Of course, the NYPD knew that it was Suzie Kingston in Chico's, but we couldn't prove it!

We couldn't positively ID the murder weapon either, because the twins possessed two knives (wiped down with perfectly legal household cleaning products which just happened to destroy all DNA and tissue traces such as, say, the victim's blood) which were as identical as the twins were!

Twins' fingerprints and footprints are usually very similar but still different, but these two were the children of a mother who was slightly disturbed; she wanted them to be identical in every way - and she was rich to boot. She had a Chinese doctor, as unscrupulous as he was skilled, operate on them in utero to alter and match their fingerprints and footprints. The surgery didn't show because foeti possess scaffold proteins which enable them to heal without scarring.

As their mother and the doctor knew.

Result: twins with identical fingerprints and footprints, and no physical traces of the operations whatsoever. It's uncertain how even their mother could tell them apart, yet somehow she always knew, addressing each twin by the correct name (she would emphasise the 'z' in Suzie's name, drawing it out slightly, and soften the second 's' in Susie's, in order to distinguish them), and thus the twins avoided growing up with identity problems. They, at least, knew which was which.

Facial recognition software failed to distinguish them. They'd taken singing lessons to learn how to modulate their voices...so voice print ID failed as well. They were the exact same height and weight, and their vital statistics were identical. Even their EEG readings, a desperate last resort on our part to find something to tell the bitches apart, so closely matched that a medical expert could not state beyond reasonable doubt that this set was Susie's and this was Suzie's.

Never had that phrase, 'beyond reasonable doubt', so utterly pissed us off as it did in this case. But as the twins knew full well, if we charged one with a crime committed by the other, that was by definition a miscarriage of justice. No judge would take that chance. But then the technique of Scanning Electron Microscopy with Wavelength Dispersive Spectroscopy came to the rescue, with a refinement reported in Cop Tech May '26: a new Silicon Drift Detector chip had been developed which greatly improved the scanning resolution.

The NYPD immediately applied for and got a new SEM-WDS scanner, and Forensics analysed the twins' victims' wounds again.

And at last, after months of frustration and eight slaughtered innocents, we got them.

When Manisha was stabbed, in such a way that she took several minutes to die whilst Susie gloated over her suffering and recorded it in HD (sent via encrypted Wi-Fi to a server in the Ukraine, far beyond the NYPD's jurisdiction, to be downloaded later for their mutual enjoyment), the blade nicked one of the poor girl's ribs. The new SEM-WDS scanner detected the tiny metal trace in the bone, where earlier models couldn't - and matched it precisely to Susie's knife.

We did something similar with Suzie's last victim, Jason Roberts. In his case he sustained defensive wounds to his hands, and metallic traces embedded in the intermediate phalange of his left forefinger matched to Suzie's knife. We also used the scanner to analyse hair samples from the twins, and we were finally able to prove that each was where she claimed the other was at the time of each murder. Your hair carries a detailed record of, among other things, where you've been over the last few months.

We proved Susie was not in Chico's as she claimed the night Manisha was slaughtered, and that Suzie was. We proved in similar fashion that Susie, not Suzie, was in the 53rd St. Library as Jason was being stabbed and emasculated (the latter being the COD) near the Chelsea Piers Fitness gym. Once we could charge them, we could and did obtain a warrant to seize the HD recordings and crack the encryption. The recordings make harrowing viewing for any decent human being.

In one respect, and only one, the Terror Twins were not identical:

Susie was worse than Suzie - far more cruel, inflicting wounds that killed much more slowly but certainly, and confessing to intense sexual excitement on watching her victims' death throes. In fact the recording shows her climaxing, her copious sex juices actually trickling down one bare leg, as Manisha gurgled her last, blood spilling from her mouth as she drowned in it. Oh, Suzie enjoyed what she did, to be sure, but not in a sexual sense; her kick, primarily, was the victims' fear more than their pain. But for Susie it was all about the blood, the suffering - and the death.

She further increased Manisha's torment, and hence her own cruel pleasure, by idly wondering if Parvati, Manisha's own twin, "can feel your pain right now? Did she feel my knife slowly sliding into your body and piercing your lower lung? Did she feel that delicious little twist as I pulled it out, to make the most of the serrated edge? Does she know what's been done to you, that you're slowly...ohh, so slowly...drowning in your own blood?

"Surely you've heard the stories about psychic links between twins? Don't you know that's why I chose you for killing? Actually, no, to be more accurate a nickel made the choice - if it'd come up tails, Parvati would be slowly dying instead of you. Should I make sure," she twisted the knife further, "to let her know that, by text from your phone...once you've, ooh, died in agony? I might just tell the bitch it could've been her, ooh...

"I wonder...will she even feel your death, when it happens? Mmm, I do hope so," she gloated, licking her lips and shuddering in a sexual paroxysm, touching her own rock-hard nipples. "Ohh, I am so wet right now without even touching my clit, my tiny panties are soaked; I'm flowing, dripping, look." She giggled, an evil sound, as Manisha choked anew, her eyes pleading for mercy whilst knowing too well there was none to be had from this evil creature. "Maybe she'll die, too, huh? You never know..."

Sexual arousal is a surprisingly common reaction to one's first encounter with violent death. In itself this is just a reflex, and nothing to be ashamed of...as long as you don't get hooked on it. It's believed the twins did just that when they were twelve and witnessed a woman being hit by a car. The drunk driver spun off the road and crashed, killed instantly; the woman he'd hit lived for about six minutes as her intestines slowly slid out of her ripped belly and her lungs filled with blood, doubtless pleading for the twins to fetch help.

They did...after she'd died screaming. The officer attending stated in his report that there was something about those two that made him 'uneasy'. It might've been that they seemed more excited than horrified. The girls claimed they'd arrived at the scene too late to help, but, he said, "Somehow...I don't believe that. God help me, they're just kids, but I don't believe them." But of course no-one could prove anything one way or the other, and so no-one pursued it further. Had they received proper counselling, rather than just being sent by their Jesuit parents to the local priest who spent an hour talking about God's will, things might've been different once they grew up.

Yeah, yeah, coulda woulda shoulda, and all that.

It's no excuse for what they did, and still less for what they were planning to do. Expert witnesses proved neither twin was insane or mentally disturbed (unlike their mother, whose aberration worsened through their childhood, turning into insanity when they were fourteen; they were taken into care after she killed her husband in a fit of rage and was committed) and therefore not responsible for their actions. Oh, no. They knew exactly what they were doing and that it was wrong...they just didn't care. They were unhinged, amoral, caring only for their own pleasure and enjoying the suffering of their victims.

No-one could account for how they got that way, given that they apparently had not inherited their mother's aberration; enjoying horror movies was one thing, but making your own, for real, was quite another.

To our horror, Susie had described in gloating detail to Manisha exactly how she would die, how long it would take...and how much it would hurt. Worse, she took further pleasure in telling the dying girl (she was just 18, for God's sake) that in order to increase the thrill for them, they intended to start killing schoolchildren in similar sadistic fashion, knifing lungs, perforating intestines, slitting throats...perhaps they might even, she suggested with an evil smile, force their parents to watch before murdering them in the same way.

This pushed Judge Surillo past his limits of tolerance and had the entire court screaming in outrage. A rookie cop lost it, drew his gun and pleaded with the Judge to let him shoot them there and then, saying he would gladly accept due punishment so long as they 'died as they deserved'.

"I'm sorry, son," the Judge said gently, "but that's my call to make, not yours, and the State of New York does not support capital punishment; in fact it ceased to do so before you were born. Please holster your weapon; I won't have vigilante justice in my courtroom - or anywhere in this State. I understand why, I truly do, but this is why we have courts. Bailiff?" He was gently disarmed and led out.

He was forgiven this understandable excess, receiving only a reprimand, because he was just 18 and his girlfriend of the same age had recently borne an unplanned daughter by him (unexpected interaction between medication and the Pill), and they were both very happy about it despite it being unexpected. A young father like him, decent and gentle, could easily be affected negatively by the prospect of someone being so evil as to want to hurt children for their own sadistic pleasure.

Captain Trent Parks, the CO of his precinct, also had kids, and could see where the rookie was coming from. "I totally get it, son. Hell, at your age - and yeah, I was a father at your age, too - I'd have likely done the same. I can't totally let it go, but you don't deserve more than a minor reprimand for doing nothing more than showing you're a decent compassionate human being, dammit. It's not as though you actually fired, is it? Nah. Six-month minor reprimand, firearms safety refresher course - IA insisted on that, gotta cross all the t's and so on - and a little counselling. Okay, son?"

Harvey Williams readily agreed. He kept his nose clean, the reprimand was duly wiped from his record after six months - and he now serves in my Unit as our Quartermaster for equipment and weapons. He's doing a terrific job - and now has two kids, with a third (another girl; his second is a boy) on the way. He's a good cop, and happy with his life - he deserves it.

The Twins both went down for life meaning life...in separate prisons. The ACLU kvetched that separating identical twins was cruel and unusual punishment (which is, quite rightly, forbidden by the Eighth Amendment), but Judge Surillo said coldly, "Tell that to Manisha's twin sister Parvati. How cruel, pray tell, is her punishment, to know she will never see her sister again because she was foully murdered for no other reason than pure sadistic pleasure? Does Parvati deserve it? Did Manisha? I think not!

"Let them rot, separately, in jail; let them never see each other again. Let us therefore mete out poetic justice at least. These are clearly evil, warped individuals who by their own recorded testimony present a clear and present danger to the public...particularly children. All possibility of parole or release for either is hereby denied. They should die in prison. Take them away."

Cop Tech is a bloody useful publication, lemme tell ya.

I wish we could call it a victory. But there was a tragic, brutal sequel: during the trial, Counsel for the Prosecution made the terrible mistake at one point of allowing Susie to speak for just that little bit too long...her Constitutional rights notwithstanding. She was given the opportunity to tell the Court - and therefore Parvati - that she'd made the choice as to which twin to slaughter in her diabolical 'experiment' by a simple coin toss. In other words, she screamed, gloating as she did, "it could've been you with my knife in your lung, bitch! It's too late to shut me up!" she cried with glee as the Judge, incandescent with rage, ordered her immediate removal from the Court. "Now she has to live with that!"

She was still laughing - and, the crying bailiff later reported, climaxing, he was sure he could smell her arousal - as he dragged her away.

But worse was to come a month after the trial was concluded. Parvati found her loss too profound to deal with despite the best efforts of counsellors; the note found later made it clear Susie's last sadistic act had contributed directly to her despair...exactly as the worst Terror Twin had intended. Susie had practically predicted Parvati's reaction.

She went to a gun store and bought a perfectly legal pump-action 12-gauge shotgun. She walked to the door, illegally loaded a single shell and, to the storekeeper's shock, cocked the gun. Her last words, before the horrified man could reach and stop her - he realised too late that her intent was suicide and not robbery, and thus he was a crucial two seconds too slow to react - were "Forgive me, Manisha. I am weak and cannot live without you."

The 12-gauge round did its job, and Parvati's tragic young life ended in an explosion of blood, brain and bone. It was no comfort to the NYPD that the coroner's verdict was 'instant painless death'.

Parvati was dead. We'd failed her. That, to us, was the bottom line.

But back to our current case...