Author's Note: Hi, readers. Thanks for checking out my story. While I am new to writing for the SVU-verse, I've been part of the fanfiction world for many years. I'd really appreciate reviews, as they let me know what I'm doing right (or wrong). In its early stages, this was going to be a hurt/comfort story for Olivia and Amanda, but as it took shape, it became more of a character study of Liv. Don't worry, there will still be plenty of Rollivia goodness ahead. Also, I noticed there's another SVU fic out there entitled "The Devil You Know" -this has nothing to do with that one, it's just the title I had picked out from the beginning and couldn't bear to change. Please, please, please R&R!

Spoilers: Half of this was written before the season 20 premiere, so there's nothing beyond one or two vague references to things from the current season. There are, however, tons of references to past seasons (as far back as season 9), so a good grasp of the show's-and especially Olivia's-backstory will be helpful. TRIGGER WARNING! Depictions of strong violence and sexual assault herein. TRIGGER WARNING!

Disclaimer: I own nothing, except for a couple of original characters I threw in there for reasons. Everything else belongs to Dick Wolf and NBC.

"Better the devil you know, than the devil you don't."
- PROVERB

"You're one microscopic cog
In his catastrophic plan
Designed and directed by
His red right hand"
- NICK CAVE & THE BAD SEEDS

PROLOGUE

A flash lights up the room, so bright it makes me see spots. For a second, though, I catch a glimpse of her, and it leaves an afterimage behind my eyes, like she's burned into my brain.

I'm positive the flash or the sound of the camera spitting out its Polaroid will wake her, but she doesn't move. I even flap the picture over her while it develops, and she keeps right on sleeping. She's so pale and still in the moonlight coming through the curtains. I wonder if that's what a dead person looks like.

Suddenly, she rolls over and mumbles something in her sleep. It's my name-mine!-and that excites me more than the risk of getting caught.

She knows me. Even without looking, she knows exactly who I am.

CHAPTER 1: Doppelgänger

The dead woman bore an uncanny resemblance to Olivia Benson, enough so that Fin took an involuntary step back and swore beneath his breath. A quick glance around at the grim faces of his colleagues assured him he wasn't alone in his assessment. Even the ME kept sneaking uneasy looks at the corpse's pallid face as she waited for the thermometer to beep, announcing liver temperature. But it was Amanda Rollins who looked greenest around the gills as she knelt beside the lifeless brunette sprawled among the Central Park bramble.

"You see it, right?" she asked, peering up at Fin from behind a sweep of blonde bangs. She tossed them from her eyes absently, blue irises flashing with an intensity that Fin had come to know—and sometimes dread—as all Detective Rollins.

"Yeah," Fin said, nodding reluctantly as he continued to study the gruesome scene. Poor lady didn't have a stitch on. If he had ever been curious about what lay beyond his boss's modest cotton V-necks and streamlined slacks, he was getting a pretty good idea right now. Not that he ever had, of course . "Yeah, I see it."

"She's got the mark, too." Reaching out with a latex-gloved hand, the other hovering near the victim's torso for balance but not touching, Amanda indicated a single vertical line along the sternum. It was the length of her forefinger and a furious shade of red. Dried blood had formed a blackish crust along the thin slice, giving it a charred appearance. Unlike the other cuts and abrasions that littered the gradually decomposing flesh in frenetic, nonsensical patterns, this was a deliberate wound, clean and precise as a surgeon's stroke.

The others all had a mark like this one. Glyphs, they were being called, no doubt coined such by some snot-nosed rookie with four eyes, no girlfriend, and a minor in ancient history. To Fin they just looked like meaningless lines and angles, dead ends on a roadmap of brutality—and yet another sign that the guy they were dealing with was a real sick twist. As if the mounting body count weren't proof enough.

"Goddammit," Fin muttered again. He had the strong urge to slip off his police issue windbreaker and drape it over the exposed corpse, shielding it from curious unis and the handful of pedestrians craning their necks behind the crime scene tape; CSU and the ME were still processing the scene, so he settled for blocking the view with broad shoulders and a wide stance.

NYPD, motherfuckers.

"Based on liver temp and rigor, I'd estimate TOD between eight and ten hours ago," the medical examiner announced to no one in particular, while scribbling her findings on a notepad. She seemed to have recovered from the eerie mood cast by the lieutenant's unfortunate double, but she was the only one. "Maybe longer with that frost we had this morning. I'll know more once I open her up."

Fin tuned out the drab voice coming from the equally drab face as it continued to monotone facts he had already heard before: lividity suggested the body had been dumped postmortem, concurrent with lack of blood spatter on scene. Obvious signs of trauma to breasts and genitals. Appeared malnourished. Oh, and cause of death? Most likely that grinning gash below the chin, stretched from ear to ear, splaying the neck open like salmon belly at a fish market.

No shit, Sherlock, he thought. Christ, sometimes he missed Warner and her dark humor. This cranky old bat wouldn't know levity if it came up and bit her on the ass.

"Straight razor," Amanda said, barely audible over a gust of chilly October wind. Her eyes were still fixed on the dead woman's face, mouth set in a taut little line, jaw clenched. She forced herself to examine the wound further down. "Bastard thinks he's Sweeney Todd."

"I hate musicals." Fin circled the body carefully, squinting at each minute detail—an oddly positioned limb, a bruise of indeterminate pattern. Anything to help nail the guy responsible for their current victim. He hoped to God the whiteish smudge on her inner thigh would finally render a DNA sample. So far the killer had been meticulous about concealing his identity, leaving not so much as a strand of hair or partial print behind. Even before he had escalated to murder—when he was still just raping and mutilating his targets—there were very few leads to pursue. According to the generic profile worked up by one of the department shrinks, they were searching for a young man (possibly a teenager, which did narrow the field a bit) who lacked impulse control and had severe mommy issues. Above average intelligence and forensic knowledge, on brazen display in his ability to go unnoticed while dumping bodies in public spaces, gave him an edge over your typical rapist. He also had a thing for tall brunettes with wide brown eyes, olive skin, and striking features.

It had been Carisi who first noticed the similarities to Benson a few months ago back at the precinct, piping up with his usual tact as they were all gathered around a collage of enlarged photo IDs, pretty smiling faces unaware of the horror in store: "Hey, Lieu, you got any sisters we don't know about?"

At that point there were only three known rapes and one homicide attributed to the man some press vulture with a penchant for alliteration had dubbed the "Manhattan Mangler." Since then, his portfolio had expanded at an alarming rate, a new victim appearing near the end of the month for the past three months.

"And now lucky number seven," Fin said, thinking aloud as he crouched beside Amanda for a closer look at the ligature marks on Jane Doe's wrists. Both were encircled by thick plum-colored bruises with a telltale braid indentation. He sighed. "Man, why'd my rope guy have to go and be a whack job?"

Amanda cracked a small smile, hunched shoulders relaxing slightly beneath the contradictory layers of a chambray button down, camel hair blazer and oversized NYPD bomber. Her bubblegum pink cheeks and occasional sniffle belied the warm attire. "Still not over that one, huh?

He humphed in reply and leaned in to examine the cluster of pink wheals Amanda pointed to on the victim's lower abdomen. Cigarette burns were a fairly new addition to the Mangler's signature, but not a particularly original form of torture among sadists. At best they were cliché compared to his handiwork with a blade.

"If she's number seven, why's she got nine burns here? Kyra had eight," Amanda said thoughtfully.

Fin decided to ignore her little slip. God knew they had all gotten too involved with this case when referring to the dead on a first name basis didn't even raise an eyebrow. But after weeks of staring at their pictures on the murder board, digging through their day planners and text messages, comforting their distraught relatives, and paying them regular visits at the morgue, reducing the women to numbers in a sequence of attacks felt nothing short of callous.

Sixth in line, Kyra Jacobs was also the youngest to die so far, just a few days short of her 28th birthday. Her identification process had been brutal; the mother screamed when the sheet was pulled back, and she couldn't look at Benson without bursting into tears. Too many unfulfilled dreams brought to an end.

The lieutenant had spent the rest of that day looking like she wanted to puke.

"Who knows with this freak. Maybe he can't do math." Fin got to his feet, swiping dirt off the knees of his pants and trying not to feel so relieved when an officer stepped forward to cover the body.

Amanda shook her head and remained bent over the corpse, barely seeming to notice the white sheet that now concealed it. "Nah. He's smart. Otherwise we would've caught him already. Maybe there's more vics we haven't found yet?"

"Could be, but why hide some and practically drop the rest on our doorstep? He gets off on this shit, Rollins. We're out here chasing our tails while he carves up pretty girls like Sunday brisket." Fin snapped off his latex gloves, wadded them into a ball and sunk it the nearest garbage can without a glance. Cause for raised fists and a slap on the back from Carisi during happier times.

Brow furrowed deeply, Amanda shook her head again and stood up. "It's gotta mean something. We're this close to finding the dirtbag, if we could just—"

"Well, that's great," Fin said, cutting her off mid-sentence and mid-step as he headed for his black Crown Vic parked among the half-dozen patrol cars that lined the street. "Let me know when you bust him. I'll be back at the house trying to ID our Jane Doe."

"Hey, what's your problem?" Amanda trotted ahead to block his hasty retreat, hands up in surrender. "I don't like this anymore than you do, y'know."

She sounded more confused than angry, and a twinge of guilt instantly diffused Fin's ill temper when he met her questioning gaze. Like it or not, big bad Sergeant Tutuola had a soft spot for the pert blonde detective. The Georgia twang and kid-sister ponytail swishing perpetually behind her had a way of wheedling into your affections after a while. If he was being honest with himself, he felt more fondness for Amanda than just about anyone else, save his son and grandchild.

Or maybe he was getting soft in his old age.

"Sorry," he said, bumping her shoulder with his own. "Didn't mean to lose my cool."

"You? Never."

Fin smiled. "Right. Man, I hate this case. And now I gotta go bother the lieutenant on her day off and tell her someone else got sliced and diced. 'Hey, Liv, call the nanny. Got another hacked up body with your face on it.'"

"That what's really bugging you?" Amanda asked gently, feigning interest in the boot she was scuffing in a patch of curbside gravel. "Having to tell her... or is it trying not to imagine that's her lying over there in the dirt?"

He kicked at a pebble she had dislodged from the ground, and they watched it sail into the street like they were skipping rocks on the lakeshore. "Little of both, I guess. She barely gets quality time with her kid as it is. Doesn't need to spend it looking over her shoulder, wondering if she's next."

"This might not be about her. Serials all have a type. The resemblance to Liv is probably a coincidence."

Even as the words left her mouth, Fin could tell she didn't believe them. Neither did he. And neither, he ventured, would Olivia, although she stonewalled most attempts to talk about a possible connection between herself and the Mangler victims. His ass would get canned for sure if he so much as breathed the phrase "security detail."

Benson's stubborn streak drove him damn near crazy at times, but it was also one of the qualities he admired most in her. They didn't come more steadfast and true than his lieutenant.

"Want me to call her?" Amanda offered, head tilted in sympathy. Her ponytail hung sideways, fluttering in the breeze.

"Nah," he said, with a light chuckle, "I can handle the boss lady. Do me a favor and make sure those bozos don't screw up our evidence, though." He motioned over his shoulder at the group still milling around the corpse and picking through the brush nearby. "I wanna nail this prick. Sooner, the better.

"Copy that, Sarge."

Amanda spun on her boot heel, moving with a quick, clipped little stride and snapping several heads to attention with a bellow cultivated by years at the racetrack and other noisy sporting events:

"All right, people, let's get this processed and back to the lab ASAP! Let's go!"

Fin watched after her for a moment with a swelling sense of pride. Then it was right back to cop mode.

Chapter 2 coming soon!