Incidentally, I totally don't hate Cassidy. Before writing this I went and watched all the Cassidy episodes to see what all the fuss was about and I actually kind of adore him. In season 1. He's so dopey and cute; I just want to pat him on the head. And while I don't hate Cassidy 2.0 either, I just don't get him. I don't think the character they wrote for him in season 15 really matched the acting, which in turn didn't match the guy I think Cassidy would have turned out to be. All that cognitive dissonance kept making me think he was hiding something, and that's what really triggered this plot. I'm probably not terribly fair to his character in this story, but I think even canonically he's done some pretty sketchy things. And let's face it, no one's a saint in this one.

4. Assumptions

Despite telling himself he wouldn't, Elliot found himself at the Sixteenth Precinct a week later, drawn there as inexorably as a moth to a flame. What finally broke him was a phone call from a lawyer, asking to talk to him about Olivia Benson's will and estate. He managed to respond politely, making an appointment instead of throwing his phone into the street. But after he hung up, he got in his car and drove, speeding down the street almost before he knew what he was doing.

It was real, he thought, shivering at a traffic light. Sometimes it almost seemed as though the last few days had been nothing but a dream, a nightmare that had somehow lingered into the daylight. But no one ever dreamed about bureaucracy, no one ever thought of the paperwork, all the little ways the world started to purge you from their records until there was nothing left but wisps and memories.

When the car behind him honked furiously at him to drive forward, he was grateful.

The station house hadn't changed much since he'd last come, the brick facade implacable as ever. The inside wasn't much different either, the walls slightly more yellowed, but still filled with frazzled secretaries and tired cops in both suits and uniforms.

Memories of Olivia were everywhere, laying in wait like emotional shrapnel mines. The elevator where they'd laughed together, debated cases under their breath to keep others from listening in. The hallway where she had tazed a man high on PCP, her eyes as cool as a mountain stream. The interrogation rooms, where Olivia had spent so much of her time, wheedling, consoling, or berating, whatever got the job done. Watching her had been like watching a master chess player, an artist, playing the emotions in the room with instinct and skill.

Now she'd never walk these halls again.

When he finally reached the squad room, he almost turned back, his mouth dry, his palms slightly damp. The thought of facing his old team like this was daunting. The reasons for his self-imposed exile from SVU came roaring back, having compounded with every year that passed. He'd feared seeing Olivia again, feared seeing blame in her eyes for what had happened, contempt at him for leaving. But now he found himself anxious at seeing the rest of the team too, of seeing Cragen's disappointment or Fin's scorn.

But before he could stop himself, he walked inside.

The squad room had changed too since he'd last been there. The desks were laid out differently, the holding cells were gone. New photographs sat on tables, with paperwork splayed out in new patterns of organized chaos. The room was almost empty, Cragen's office dark, the door closed. Only one detective was at his desk, his brow furrowed, a report in his hand. It was the dark-haired man from Olivia's funeral. Her new partner.

As if he'd heard the thought, the other man glanced up abruptly, standing up and setting the papers down.

"Can I help you?"

"Who are you?"

He walked over, his handshake brisk. "Detective Nick Amaro. And you are?"

"Elliot Stabler."

"What can I do for you?"

"Is Detective Munch around?" The formality felt strange on his tongue, but he didn't want to invite the questions that came with too much familiarity.

"He's working a case, sorry."

"What about Detective Tutuola?"

"Also busy."

Elliot tried for a disarming smile. "Holding down the fort all by yourself, huh?"

Amaro didn't smile back. "It's been a rough couple of months. What do you need? Maybe I can help you."

He considered it. "No. I'll catch them later. Thanks."

He'd already turned to go when the other man's voice stopped him.

"I remember you. You walked out of the funeral."

He froze, then turned. "Yeah. I didn't mean it as an insult. I just..."

"I know." Amaro watched him, unblinking. "I recognized you. You were her old partner. She had a picture of the two of you on her desk."

"Oh."

"Haven't seen you around though."

"No. You wouldn't have."

Amaro scrutinized him carefully for another moment then shook his head. "Look, something obviously happened between the two of you, and maybe it's none of my business what. But she clearly cared about you, and you're here now, so maybe you still care about her. I'm not Fin or Munch, but if something's on your mind, I'll tell you what I can. I was her partner too, you know."

Elliot hesitated for a moment. "I just want to know how something like this can happen."

"I wish I knew. I can only imagine a couple dozen people are about to lose their jobs"

"How did he escape?"

"They're still looking into that."

"Okay, how was he gone for a whole weekend before anyone noticed? You can't tell me they haven't figured out how a prisoner can go missing for two days without anyone the wiser."

"From what they're saying, it looks like it was just a paperwork issue. He was being transferred from Rikers to Bellevue on Friday, but Bellevue didn't expect him until Monday. The place is a shithole. In a way, it's not surprising."

"There's no way that just happens. No one's that lucky. He had to have someone helping him, someone on the inside. Did you check his friends, associates?"

Amaro shot him a look of stony annoyance. "Yeah, we did remember to do the absolute first thing we're supposed to do. It might surprise you, but we're not complete idiots."

"Sorry," Elliot said quickly. "I didn't mean -"

"No, I'm sorry. I overreacted" Amaro rubbed at his eyes. "It's just - He's beaten us twice now. Reporters are talking about him like he's a genius, but he's not. He's impulsive, makes too many boneheaded mistakes. But his strength is understanding people. He sees someone and instinctively knows how to charm them, manipulate them, make mistakes in his favor. But it doesn't last. People start to see through him. When we first came across him, he was living at a halfway house and everyone there hated him. There's no one that would put themselves on the line like this by helping him."

"What about family? People get pretty crazy about blood ties sometimes."

"The mom died giving birth, the dad died ten years ago. He has an aunt on his mother's side living somewhere in Nebraska - there's no indication she ever even met him."

Elliot let out a breath. If Amaro was offended by his question earlier, he definitely wouldn't like this one. "No one checked on her all weekend? No one gave her a call, stopped by her place? Especially after what happened before?"

The pain in Amaro's eyes was deep and cutting, tinged with self-loathing. "We did for a while, after she was abducted last summer. She hated it. She hated anything that reminded her of what happened, every way that anyone wanted to treat her differently. After a while, we got the hint."

Elliot nodded. That sounded like Olivia. And he had no right to condemn them anyway. If Amaro had failed in his duties, Elliot had been a thousand times worse.

Amaro was still talking. "Besides, she didn't live alone. She moved in with her boyfriend a couple months ago. "

"Boyfriend?"

"Yeah. But he wasn't home. She managed to date the only cop on the planet who works more than her."

Elliot narrowed his eyes. "And he was gone because...?"

"IAB said they had him on an undercover op all weekend."

"She was dating a guy in IAB?" He would have been no more surprised to hear that she had quit SVU to open a pie shop on the moon.

Amaro almost managed a chuckle at his expression. "He only joined IAB a couple months ago. You might have met him before. Apparently he used to work at SVU, back when Olivia started. Brian Cassidy."

The name rang only the faintest of bells.

"What's he like?"

Amaro hesitated. "I'm not the best guy to ask about that. We've had our problems. Most people would tell you he's a decent guy, works hard."

"And what would you say?"

"I wouldn't disagree. We're never going to be close, but that doesn't mean he's a bad person. He obviously cares about Olivia a lot, and he makes - made her happy. That's all I need. It's just that if a guy punches you in the face when you first meet, you're never going to be best friends."

Elliot chuckled slightly. "I've made a couple friends that way, actually."

Amaro's expression didn't change. "There were other things too."

"Like what?"

"Like things that are none of your business."

Elliot took the hint. "IAB offices still in the basement?"

Five minutes later, Elliot walked out of the elevator, brow furrowed, nearly bumping into the man in front of him. He was trying to dredge up his memories of Brian Cassidy, but he found there weren't many. He'd lasted less than a year at SVU, burned out by the endless parade of tragedy. He had indeed been a nice enough guy from what Elliot could recall, young for his age but sincere and well-meaning. But not a man he would have ever imagined Olivia dating.

Dimly, he recalled that Cassidy and Olivia did have a fling fifteen years ago. He knew only because Olivia had told him about it afterwards, wearing the look she had whenever she thought she'd screwed up a case. He remembered feeling vague pity for the guy, who was obviously head over heels for her, but not quite within her league. But they'd ended up together after all.

Consumed by his thoughts, Elliot missed the door to the IAB offices and was forced to backtrack several feet, the muscles in his chest tightening slightly as he approached.

He'd never come here willingly on his own - usually he ended up in these basement rooms after an act of death or violence. He expected some echo of memory, some flashback to his final interrogation where Ed Tucker had stared down at him with cold accusation as he felt the warm drip of blood from his hands, even though he'd washed them clean dozens of times already. But there was nothing. IAB's squad room looked no different than anyone else's, desks scattered about, covered with half-finished paperwork. It was largely deserted at the moment. Only Brian Cassidy was there, sitting in a desk in the far left corner, his head in his hands, his shoulders slumped.

Watching him, Elliot felt a surge of compassion. If there was one person here who might understand what he was feeling, it would be Cassidy. However surprised Elliot was at their relationship, he'd apparently loved Olivia too, and now was not the time for petty jealousies.

"Hey," he said, and Cassidy jumped, as though someone had punched him unexpectedly.

Seeing him close up, Elliot understood why he'd felt no flicker of recall upon seeing him at the funeral. The Brian Cassidy of his memories had been marked by artless naivety, enthusiastic boyishness shining from his face. The man staring back at him now brought to mind a wary stray, closed and cautious.

"Uh, hi," he said uncertainly. "Can I... help you?"

"It's Elliot Stabler. We worked together way back. I was Olivia's partner."

He saw recognition slowly dawn on his face.

"Oh yeah. I thought you looked familiar. It's been a long time.

"Yeah."

There was a long, awkward pause, and Elliot wondered why he had come. For information, commiseration? To try and understand this man that Olivia had finally deemed worthy? To ask -

Where were you when it mattered?

But no, that would be the wrong thing to say right now. Elliot needed to believe that she'd been happy before the end, needed to believe that she'd found something for herself outside of her job.

"I heard you two were together," he said instead. "I'm sorry for your loss."

Cassidy looked away, clenching his jaw and blinking away tears. "It's, uh, still hard to believe sometimes."

"Grief takes time."

"I know."

"How'd you two end up meeting again?"

"We met on a case two years back- big prostitution bust - you might have heard about it on the news. I was undercover for a guy named Bart Ganzel, one of the kingpins. He turned up on SVU's radar too, and when Olivia and I ran into each other we just hit it off."

"That's good."

The silence was longer this time, tension hanging oddly in the air between them. It brought to mind two dogs eyeing each other, unsure of whether to bare their teeth or wag their tails. Elliot had never had much to do with Cassidy even when he was back at SVU but he never would have guessed back then that this was how the man would turn out. Had they really been dogs, the Brian Cassidy of his memories would have been a puppy, tripping cheerily over his own paws, eager to show you the pine cone he'd found by throwing it up all over your shoes. Fifteen years later, he'd returned as the grown dog, but one who bore the distinct aura of being kicked once too often, who stared back at Elliot with a sense of hooded caginess.

What happened to you when you were undercover? Elliot wondered suddenly. Something bad, he suspected. Something beyond the typical law enforcement descent into cynicism.

Cassidy cleared his throat uncomfortably. "So uh, how long were you guys partners?"

"About twelve years."

The other man's eyebrows shot up. "That's - wow. So you didn't split up that long ago."

"I put in my papers a couple years back."

"It's weird, you think she would have mentioned you. She talked about work like all the time."

Elliot shook his head. "There were some... issues near the end."

"Right. None of my business." He glanced away. "Look, thanks for stopping by, but I've got a lot of stuff left to do - "

"I'm surprised you're back at work already. You'd think they'd give you more time off after what happened."

Cassidy stared at his desk, his eyes haunted. "I'd rather keep working. Time off just gives you too much time to think."

"I know the feeling." Elliot extended his hand to shake. "Again, sorry for your loss. Let me know if you need anything."

"Thanks."

Elliot went home.

It wasn't until later that night, in bed, nearly drifting off to sleep, that a sudden thought jolted him awake. There had been nothing particularly unusual about his meetings earlier. Nothing untoward or suspicious. But today had been a day of too little information and too many assumptions. And as any detective could tell you, assumptions could be very dangerous. Assumptions led to cold cases, false convictions. Assumptions made you miss things you should have seen from the start. And when a woman was killed, who was the first suspect? Who was the very first person whose life you should examine? Why, the boyfriend of course.

He rolled onto his back to stare at the darkened ceiling, feeling oddly guilty for even entertaining the thought. More for Olivia's sake than Cassidy's. She would never have let anyone into her life that she wasn't completely sure about. He might not know Cassidy anymore but he knew her.

But then again, who would be more capable of deceiving a detective than a career undercover? One who'd spent a decade playing someone else, who'd worked his way into the good graces of the savviest of criminals, who had in fact likely spent more time around those on the wrong side of the law than those on the right?

It was an absurd thought. Yet it remained, hovering in the recesses of his mind.

Sleep didn't come that night.