Mackenzie Riley walked with purpose into the reception of the NYPD's criminal investigation building.

This was where all the real work was done, at least in her opinion. Most in her position considered their jobs to be of the utmost importance. They considered their jobs to be the ones that saved lives and caught killers. Not Mack. Mack knew it was the science, the DNA matches, the evidence that proved guilt and the people who worked so hard to prove it, was the thing that put people behind bars. She thought of herself as a mediator. The one who was given the proof and in turn was able to knock on a door with a set of handcuffs and drag them away.

It had been awhile since she had stepped foot in here, not since she'd been a beat cop could she remember walking into the intimidating building with it's many floors and people running around in lab coats. She politely stopped at the reception desk and asked where she could find Detective Mac Taylor, thanking the sweet receptionist who had pointed her in the direction of the lifts and told her which directions to take once she reached the right floor.

She stepped into the lift and pressed the button, waiting impatiently for the doors to close and the cubicle to elevate. She'd always hated lifts, found them ominous. Petrified that one day she'd step into one and for one reason or another never be able to step back out. Her heartbeat intensified until the ring of the bell signaled the opening of the door, coaxing her back out of her nervous state as she placed one foot in front of the other and began to walk down the hall.

The clack of her heels on the linoleum floors caused a few people to look up and stare, it wasn't everyday that someone like Mackenzie walked through here. On the inside she was sweet, caring, quiet and reserved. Smart as hell, compassionate and kind if not sometimes a little passive.

Of course, not too many people got to see that. On the outside she was intimidating, tough. She stood as tall as she could, ramrod straight and with intention evident in every step. She'd thrived to be taken seriously from day one. Girls that looked like her had to work hard to be respected when they started out.

Today she was dressed in black from head to toe, but not like one might expect from an F.B.I agent. She had on the heels of course, all five inches of patent pump glory. Shoes which most deemed impossible to run in, but she always found a way, and hadn't injured an ankle or a knee yet. Her skirt was almost skin tight and sat just above her hips and came down a couple inches past her knee, the faint white pinstripe on the black fabric lengthening her legs.

In place of an expected blazer or typical white shirt was a black cardigan which looked as if it had come straight out of a 50's pin up calendar with it's three quarter length sleeves and button up front. It's body stopping just as the waist band of her skirt started. Her face was framed by long, straight, dark hair with a side fringe, undone and casually pushed out of her face in contrast to the very proper and disciplined nature of the rest of her outfit. Black rimmed glasses sat perched atop her nose through which chocolate brown eyes lined with a single stroke of liquid eyeliner on the upper lid viewed the world. The only thing which stopped her looking like a 'naughty librarian' as her best friend had jokingly put it, was the belt she wore around her hips which held the regulation 9mm hand gun and her F.B.I I.D badge.

She hadn't always dressed like this. She had become very used to dressing pretty masculine. From starting out in the regulation police officer's uniform to the suit's she wore when she first started with the FBI. In her own mind, she had earned the right to dress this way. She had put in the hard yards and long hours and gained the respect from her colleagues which made her feel more comfortable with dressing more femininely. She was diminutive, standing only at five foot four when she didn't have heels on and weighing only around 123 pounds, but the confidence and toughness she had aquired as she gained respect when she was a cop made for a formidable appearance.

The glass walls which surrounded her gave her insight into what life was like in here. Centrifuges and computers, audio visual analysis equipment, she'd loved it all. Observed it all before, and if she'd been any good at chemistry when she was in school it would have been the path she'd taken. Alas, science had not been her strong point. But being passionate about justice and standing up for what was right and wrong, being able to stand up to people who thought they could push her around because of her small stature or shy nature, that was.

There were people who had laughed when she'd gone into the police academy, but she'd always loved proving people wrong. And when she'd graduated first in her class, she laughed right back in the faces of all the people who had told her she couldn't do it. Of course, there was one person, a certain guy who she'd met at the academy, who never questioned her ability, never questioned her toughness or integrity. A guy she didn't like to think about too much because, without trying to sound like a Harlequin novel, it made her heart ache.

They'd spent a great amount of time together, the academy, joining the NYPD. He was promoted to homicide detective shortly before she was offered the same promotion, only it was around this time that things between them weren't so great and so they went their separate ways. It had been far harder for her than she'd let on, and when she was offered a position by the FBI, she decided it would be a good idea to take it, decline the homicide position and move as far from him as humanly possible. She couldn't see him everyday the way things had happened, the way she felt it hurt too much. So she packed up and she left.

What had happened to him? She didn't know, they hadn't spoken in a long time. Around four years. And while she was anxious about being in New York again, she just kept reminding herself that it was a big city and that the precinct she was going to be working with, it wasn't even the one he'd worked for.

Mackenzie shook the thoughts and the image of his face from her mind, took a deep breath and knocked on the glass door in front of her.

"Come in," a male voice replied, authoritative but warm at the same time. She pushed open the door and stepped inside, closing it behind her.

"Detective Mac Taylor?" she asked hopefully, already knowing the answer but wanting to be polite and assured that this was indeed the right person.

"Agent Riley I presume," he replied after he nodded, standing from his seat and putting out his hand for her to shake.

"You can call me Mack," she began taking his hand in a firm shake before letting go, "Though considering your name, that might not be the least confusing thing."

The two of them laughed lightly at their shared name before she spoke again.

"On second thought, you can call me…well, anything you like really. But Riley is fine," she smiled as Detective Taylor lead her out of the office and down the hall towards a larger conference room with the CSI's working this case no doubt.

"Riley it is," he obliged as they walked, "My CSI's have just finished processing the evidence from the last murder, I've asked them to meet us down here so we can let them know what's going on."

Mackenzie liked when Detectives used the word 'we'. It meant that they saw she and them as equals who needed to put in the same amount of hard work and effort in order to meet a common goal. She could tell even without knowing more about him that Mac Taylor was a man of integrity and honour who viewed himself as just one person in a large group of individuals who all had something important to offer rather than a Detective with a God complex.

"Sounds like you're all sorted," Mackenzie stated, flicking through the file she had opened in her hands.

"So I'm at work five minutes and I get a call saying they're sending you and that's all. When exactly did this case become the F.B.I's business?" inquired Det. Taylor.

"When a murder with a matching MO was reported in Vegas. I've already been down there, this is what they got. It was red flagged in the system, evidence seemed too similar to your cases to be an accident. You get me," she explained as Det. Taylor nodded in understanding and opened the door to a larger room in which sat five tired and almost disgruntled looking figures.

Three men, two women.

"Guys, this is Agent Mackenzie Riley, FBI. Agent Riley this is Danny Messer, Lindsay Monroe, Stella Bonasera, Sheldon Hawkes and Adam Ross," Det. Taylor said, introducing them all.

Mackenzie gave a friendly but professional smile in each of their directions before setting her files out on the table before her.

"You're a fed?" asked the one she now knew as Adam as his eyes grew wide with surprise, taking her in, "Add tattoos and you could be a Suicide Girl."

Mackenzie wasn't unused to this response, but it still made her a tad uncomfortable, a fact she realized she did bring upon herself. But she was at the point in her life and career where she knew how hard she worked and was able to joke about it knowing she was well-respected.

"I used to be," she said with a dead pan expression as they all looked on with gaped mouths.

"It was a joke," she smiled, lightening the mood, "Feds, we make jokes too sometimes."

This seemed to loosen the tension in the air which was always apparent when she became involved in a case. Cops and CSI's alike tended to see feds as an interruption and an unnecessary addition to a case. As if they were going to take everything over. And sometimes even Mackenzie had trouble reminding herself that wasn't true. There were of course some FBI agents who viewed their status and their role as being of greater importance and thusly treated police officers, detectives and CSI's like trash. Mackenzie just wasn't and never would be one of them.

"I was just telling Det. Taylor that the reason they sent me is because there was a murder in Las Vegas which bore a striking resemblance in methodology and evidence to several murders that were committed here. Almost identical. Now this could be any number of things. Copycat, the actual killer moving around, someone trying to run us off down a bunny hole, which is why the evidence from the Vegas lab has to be compared with the evidence here," she explained clearly to the detectives who sat before her, paying undivided attention.

She hadn't always been so comfortable addressing groups of people, but she'd learned along the way, along with shooting a gun and taking down an assailant, that it was something she'd have to just get over the fear of and do. And now, she did it pretty well.

"I take it you have the evidence here?" asked Stella eagerly.

"That I do. Statement's from witnesses, D.N.A. analysis, coroner's report, trace, photos. You need it, I've got it all just here," she explained, gesturing to the thick folder she had just placed down, "Also, I need to speak to Detective Angell seeing as though she was the detective assigned to the murders."

In all honestly, she'd breathed a sigh of relief when she was informed by her superiors of the detective working the case. A Detective Jennifer Angell. With all the anxiety and paranoia in the world, she had been terrified that it would have been him working the case. If it had been, it would have been just her luck. But thankfully someone up there was looking out for her and had not deemed it necessary for it to be him and his cliche tall, dark and handsome figure with that brown hair and those clear blue eyes distracting her from her job. With him looking like that like he always had and the awkwardness that would have no doubt resonated between them had they been in a small room sharing the same air after not even sharing a time zone for the past four years.

"She's on medical. She was shot last week and is still in the hospital," explained Det. Taylor as he sifted through the Vegas evidence.

"I'll need to know the name of the detective taking over for her, for my superiors, paperwork, you know," she replied, picking up a pen and bending down over the blank paper in her file to write down the name.

Mackenzie shrugged, it wasn't a big deal. She would need to speak to Angell as well, but as long as their was a Detective to overlook the investigation and keep her informed of their protocol and any leads then it was going to be fine.

"That'd be Flack," stated Danny nonchalantly, taking a sip from his coffee cup and rubbing his face to ease the exhaustion.

Mackenzie's body froze at that name. Her body was paralyzed an she was sure that her face had gone as white as a sheet. She felt numb and hot and cold all at the same time. She couldn't move or think about anything but his face.

'Please let it be any other Detective Flack' she prayed as she blinked and breathed in heavily, her heart racing as sweat built at her temples and she suddenly became very warm.

"Do you mean Detective Don Flack?" she managed to stutter out, trying and failing to sound relaxed and indifferent. Desperately hoping the answer would be no. That it would be any other name. Any other name would have been fine. John, Jim, Bruce, Ken, Ryan, Keith. ANYTHING other than Don and she could have pulled herself out of her state and breathed a sigh of relief.

But unfortunately on this day when it came to this subject, Agent Mackenzie Riley realized she didn't have any such luck when an all too familiar voice resonated behind her.

"Did someone say my name?"