A/N: So I was definitely in the mood to write a triple crossover.

Jennifer Jareau smoothed her hair, blinking tiredly at her office computer screen. Both Henry and Michael had been up all night with a sinus infection. She could feel herself drifting off, but not before her phone began buzzing. "Agent Jareau," she answered.

After listening intensely for fifteen minutes, she hummed in approval. "Yes, yes, we got your case last week. We reviewed it and I was about to present it to my team. No, you didn't bother me. Yes, we should be there by the end of the day. Your welcome. Goodbye, Captain Benson."

Jennifer shook her head, stood up, and headed to the conference room. Stopping by the bullpen, she cleared her throat. "Guys, we have a case." She grimaced as the smiles on her coworker's faces faded slowly.

The team paraded into the conference room, taking their seats silently. Garcia seized the remote, turning on the plasma screen television. She sighed wistfully. "Ok my lovely moppets. There is a total of twelve bodies in New York City, all raped, all stabbed repeatedly then shot in the head and the private parts respectively. The victims are all elementary and middle school students, varying in sex and race. What makes this case special, beyond especially gross and especially weird, is the fact that each killing alternates between two boroughs. They are all Manhattan residents, raped in their home before being transported to Brooklyn for the killing. The unsub also has each victim call the police after the rape, reporting both the rape and the location. Manhattan's Special Victim Unit contacted us a week ago, stating that their unit has been collaborating with Brooklyn's 99th precinct. However, last week, their 12th body was discovered and they decided they needed extra help. It's been six months and they still haven't caught the guy."

Hotch studied the display of pictures on the screen. "There's obvious overkill on each body, and it's rare to see an unsub without a particular preference to gender or race. Most pedophiles stick with one or the other. The fact that the killings are also occurring at a steady rate with no clear pattern of escalation indicates that the unsub has excellent self-control. These are children, and this is urgent. Wheels up in thirty."

Olivia winced as she set down the phone. She knew her squad was territorial, and their reluctance to open up their territory to the 99th precinct was already adamant, but now she had to announce that the feds were called in. She walked into the crowded pen. "Guys. As you know, the Double Boroughs Killer is up to its twelfth victim in six months. We've already been working with Brooklyn's 99th precinct. But, both Captain Holt and I have decided that there is a bigger force at play. Last week, we put in a request to have the FBI's behavioral analysis unit consult on this case. They should be arriving later today. Now, the 99 is sending their five best detectives, as well as Captain Holt, to help consult on this case. We're going to be working in the larger conference room. Agent Jareau, the BAU's communication's liaison, has requested that we set up a timeline and victimology board. Carisi, since you went to the FBI's profiling seminar, I'm going to have you do that. This perp has raped and killed twelve people, consistently alternating between Brooklyn and Manhattan. We've been chasing him for months and its time we catch the son of a bitch."

The squad nodded, dispersing outwards to do their assigned jobs. It wasn't an hour later that Captain Raymond Holt stood tall in the middle of the bull pen. He was surrounded by six people, who were squabbling amongst themselves. Hushing them, Holt turned to Olivia. "Hello, captain Benson. I'm Captain Raymond Holt," he said, stretching out a large hand.

Olivia smiled. The man had a kind but firm gaze. She took his hand and shook it resolutely. "And who did you bring?" she asked.

Holt stepped to the side, revealing his gang of bickering coworkers. "Settle down, have you no manners?" he barked.

This caused one of the people, a smartly dressed female with dark hair pulled back into a ponytail, to snap away from the group, looking remotely ashamed. "Hi, I'm detective Amy Santiago," she said, smiling warmly.

Before Olivia could shake Amy's hand, a man-boy with unkempt curls bumped into her. "Sorry Ames," he said apologetically. He turned his gaze on Olivia. "Hello captain, I'm Jake Peralta, captain Holt's favorite detective, and a shoo-in for winning life," he said, with a crooked smile.

Olivia couldn't help but smile back. Holt interjected. "And this is detectives Boyle, Diaz, and sergeant Terry Jeffords," he finished, snapping at his squad to get their act together.

Olivia snickered as one of the most well-built men she's ever seen in the department turned around with a facial expression akin to a kicked puppy. She merely led the large crew into the conference room. Carisi, who had busied himself with creating the victim board and timeline, turned around, greeting the newcomers with a surprise. "Dominick," he drawled. "But you can call me Sonny," he added.

Boyle scrutinized Sonny carefully. "Didn't you work Brooklyn SVU?" he inquired.

Sonny nodded enthusiastically. "Yeah! For about a month."

Boyle smiled approvingly. "You consulted on a case with me- the Bodega Ripper," he quipped.

Carisi's eyes widened in recognition. "Yeah I remember you!"

Boyle, Carisi, and Peralta broke off to discuss the details of their past case. Olivia pulled Captain Holt aside. "I just got a text from Agent Jareau. The Behavioral Analysis Unit will be landing in an hour. Carisi has the victim board set up, and I have Rollin's down at the M.E pushing for the DNA results."

Holt nodded curtly. "That is excellent," he remarked, expression unwavering. "I am aware that you work with ADA Barba?" he inquired.

Olivia bobbed her head in affirmation. "Yes, we are. He's taken a special interest in this case and would like routine updates as we reveal more about the perp."

Holt stared at her intently. "Yes that is fine. I am familiar with ADA Barba from his days in Brooklyn, and I am completely confident in his ability to prosecute this case."

Olivia gave the tall man a slight smile. "He's one of the best members of this team," she said reverently.

Hotch worried his lower lip as he observed the file J.J had handed him. The crime scenes were neat, just a corpse left with minimal forensic evidence. The Unsub seemed to bleach each body before posing them at various playgrounds and elementary schools. His heart sank as he came upon a photo of a child no older than eight, left in the fetal position on a park bench. Kids were always the worst, and the thing he worried about the most was how this case would affect his team. He was also partially worried about the department relations. He had done his brief research into Manhattan's Special Victim Unit and Brooklyn's 99th precinct. He was aware of the very recent death of sergeant Michael Dodds, and was wary of how the precinct would react with the FBI taking over. He knew that regularly, there were existing tensions between the feds and the local cops, but he made a note to take extra care on this case, as Manhattan's SVU was prone to high publicity. Brooklyn's 99th precinct was slightly less tense, but Hotch had noticed that both a captain and a lead detective had returned from being in the Witness Protection Program, and worried about atrophying detective skills came to mind. Shaking off his fears, Hotch pulled himself back to the moment. "Spencer," he said, drawing out the genius' name and looking at the file critically. "What do you think of the victimology?"

Spencer squinted at his copy for less than a minute. "Like you said before we left, it's exceptionally rare that we see an unsub that chooses both boys and girls. What makes this even rarer was the fact that these children vary in both race and age. Normally pedophilia and ephebophilia are mutually exclusive. There's also no pattern in the victimology, which means these are all probably victims of opportunity. He's abducting high risk victims which means that he's very smart- which is evident further in his ability to evade capture."

Hotch nodded in agreement. "When we land, I want Rossi and Morgan to go to the crime scene and I want Reid, Prentiss, JJ, and myself to meet up with Captains Holt and Benson."

The team signaled their comprehension. The plane landed roughly on the tarmac, and they hurried outside. Hailing a cab, the team made their way to Manhattan's special victim unit. As the cabs pulled up to the curb, the team climbed out, entering the police station. Hotch flashed his police badge. "Special Agent Aaron Hotchner, I'm consulting with the Special Victims Unit, a captain Olivia Benson knows of our arrival."

The secretary smiled. "Alright sir, please take the elevator to the third floor."

Hotch obliged, leading his team onto the elevator. Pressing the button, he held his breath. The elevator opened, revealing a busy squad room, bustling with people answering phones and doing paperwork. A woman with dark hair and a lean gait approached them. "I'm Lieutenant Olivia Benson. You must be the BAU," she smiled warmly at the team.

Aaron nodded curtly. "I'm unit chief Aaron Hotchner."

Olivia surveyed the newcomers critically. "I'm-I'm sorry, aren't there supposed to be more of you?" she asked politely.

Hotch ushered his team into the conference room. "I sent my other two agents, David Rossi and Derek Morgan, to the latest crime scene in Brooklyn. Olivia nodded in understanding. "Alright, well, I've got my best detectives, and the loans from the 99 in the conference room. I had one of my detectives, Carisi, set up a timeline and a victim board. You can take the lead from here."

Hotch flashed her one of his rare smiles. He followed her into the conference room, where detectives sat on various pieces of furniture. Hotch suppressed a snort. It seemed as if everywhere he went, detectives were perplexed by the idea of using chairs for sitting. Hotch made his way towards the makeshift podium at the front of the room. He cleared his throat. The buzzing of the room died down. "Hello," he said smoothly. "I'm supervisory special agent Aaron Hotchner and this is part of my team at the Behavioral Analysis Unit. I have agents Prentiss and Jareau, and Dr. Spencer Reid assisting me with this case. Agents Morgan and Rossi are at the most recent crime scene in Brooklyn."

The air was thick with anticipation. Captain Holt stepped forward. "I'm captain Raymond Holt from Brooklyn's 99th precinct. With me, I have detectives Peralta, Boyle, Diaz, and Santiago, as well as sergeant Terry Jeffords, and my assistant, Gina Linetti," sweeping his arm out, gesturing towards each person respectively.

Hotch inclined his head slightly. He was then ambushed by a tall man with slicked back hair. "I'm detective Carisi, but you can call me Sonny."

A shorter blonde woman rolled her eyes. "Nobody wants to call you Sonny, Carisi," she said. She then extended her hand. "I'm detective Amanda Rollins." She ushered towards a taller man with a dark complexion and a bald head. "This is my partner, Fin Tutuola."

Hotch made his acquaintances before turning his attention to the victim board. Surveying it slowly, he clicked his tongue in approval. "This is excellent," he admitted. "Detective Carisi, I'm impressed."

Carisi puffed his chest out with pride. "Thank you agent Hotchner."

Spencer was pacing the length of the displays. "Can someone tell me if any of the victims were connected in any way?"

Jake nearly tumbled off the table to answer the doctor. "The only link we could find was through the family. Each victim was part of a two parent household." He righted himself before squinting shiftily at Spencer. "You look like you're 20, how are you a doctor?" he inquired incredulously.

Spencer turned a shade of red. "I graduated early," he explained, snorting derisively at his own explanation.

Only semi-satisfied, Jake returned to his seat, continuing to eye Spencer. Spencer blushed harder under the young detective's gaze. Turning to the board, he was soon lost in thought. Hotch scrutinized the board alongside with him. "Could anyone tell me the connections between the two locations? There has to be one. The unsub, or unknown subject," he clarified quickly once he saw a group of bemused expressions. "The unsub is taking a lot of risk to transfer his victims across an entire borough. And nobody can tell the victims are gone until a day before the bodies are found?"

Olivia nodded. "The M.E report says that each victim was brutally raped within a day of their death, and their disappearances are reported long after they've died. Every victim they've found, the time of death dates back farther than the Amber Alert."

"And they're always found in parks and school grounds?" Spencer asked.

Amy Santiago nodded. "They're all school children who were latch-key kids, left home alone frequently. The perp had each victim call and report the rape, but by the time units reported to the scene, both the victim and the rapist is gone. The bodies are within the next 12 hours in Brooklyn. No DNA evidence, no trace evidence. It's a disappearing act."

"He's obviously got deep seated resentment towards these children, look at that overkill. And the transferal of the victims means that each location has some deep meaning towards the unsub," Terry commented warily.

Everyone from the 99 turned to look at him, including Captain Holt. "What?" he exclaimed. "Terry loves psychological analysis!" he said defensively.

They redirected their attention to Hotch, Prentiss and Reid. "What we need to do is a press release, warning all parents that leaving their children home alone should be a last resort. Recommend community centers and neighborhood day cares, but emphasize the importance of staying calm and alert," Hotch relayed to J.J, who nodded and hurried away.

"The rest of us will work the case, analyze the current crime scene and work with what we have now," he announced, receiving a unanimous response.

Hours into paperwork and theory trading, a young cadet stuck his head into the conference room. "Captains, agent," he said nervously, a bead of sweat inching down his forehead. "He's struck again."

A/N: I love all three shows and I lowkey wanted to write a three way cross over. Not my best work but not my worst.