DISCLAIMER - Not mine - belong to NBC & Dick Wolf

A/N - Thankyou to all reviewers, as you may know reviews feed the creative beast. Yeah it's lame, but sincerely, thanks!

Part 3

Concentrating on the computer screen, Olivia didn't notice that Elliot was still looking at her. One desk over, the other two detectives, John Munch and Odafin 'Fin' Tutuola were working on another case.

Fin nudged John under the desk. Munch looked up and Fin nodded in Olivia and Elliot's direction.

John was smiling broadly when Elliot looked up, scowled flushed a bright red and started shuffling his papers around.

Olivia was oblivious to the boys' grinning and nudging each other. Her computer beeped a few times and came up with a list of over 100 reports with picquering covering a 12-month period. She scrolled through the descriptions of each assault looking for the signature, not just the MO.

She finally hit on a report filed on a Lauren McNish. Printing the file, Olivia read it aloud. "Here it is, Lauren McNish, prostitute. She was found in an alleyway, strangled, and stabbed over 100 times. Raped by a foreign object, no trace of fluids."

Elliot listened attentively.

"Remember, at the time we had nothing to go off? There were no leads from the crime scene and seeing it occurred in the red-light district. We figured it was a one off."

Elliot nodded as he remembered the case, while Olivia turned back to keep searching through the files, finding an additional 3 murders with similar signatures. All had remained unsolved with few clues found at the scenes and no leads. Olivia printed off the files.

"Elliot! Check it out." She handed the papers across the table. He read through the files. The other two detectives wandered over to take a look as well.

"You know they have a different MO," Munch said.

"Oh come on John! How long have you been a detective? You know that MO isn't as reliable as 'signature'."

George who'd just arrived took the files from the other three and read through them. "Olivia's right. Now days signatures are what's used to link together multiple murders, to make a serial killer. The MO is only a staging thing. The real excitement for the killer is the psychological release that gets him off. And that's what remains the constant."

Olivia flashed John a triumphant grin, pleased that her hunch had been right. "This guy's been doin' this longer than we thought. And he's very good at it. I told you I remembered the MO. The doer has been getting away with this for a very long time."

Elliot stood, "We gotta show these to Cragen."

Knocking at the open door to get his attention, they entered when he muttered, "Come!" without looking up.

Olivia closed the door behind them. Elliot handed the files to the older man behind the desk.

"What this?" He asked flicking through the papers.

"Olivia found them." Elliot stated leaning against the closed door as he let his partner take over. She sat in a chair opposite the captain.

"That homicide that we were called to this morning, Warner said there was an identical homicide a month ago. I remembered it. We didn't have any leads, and there was nothing found at the crime scene. There was nothing to go off, until today! I ran a further search, and came up with those four additional cases.'

Cragen scanned the files. "This should have been picked up ages ago."

"Yeah, but aside from Lauren McNish, the others were committed in different precincts, and all but one of the other three were prostitutes. I know it's not PC, but they don't tend to be a high priority for most divisions. Plus, there have been no clues, no DNA has ever been found at the scenes. The ligatures have always been generic rope or twine, available at hundreds of stores all over the city. There are no leads, because who ever is doing this, is leaving absolutely no clues behind. He knows what he's doing, and he's not going to stop."

Looking up Cragen smiled a little. "You just sounded like Huang."

"Thanks. I think." Olivia said.

"Okay, what are you waiting for, go through the files, see if there's anything that you can link, and talk to George, get him to give you some kind of profile you can work off."

Nodding, Olivia said, "He's outside, and he's already agreed, that it's a signature killer."

"Okay, he's agreed. That's great. Now maybe he can give us an idea of who we should be looking for."

Olivia and Elliot left the office and started filling in the resident psychologist on what was happening.

Elliot turned to George. "Okay, so how do you propose we catch him? His 6 victims have been of different social status, and all been looked at by different precincts."

"He'll be well educated, probably white, as he only killed white women, or women of Caucasian appearance. Killers tend to stay within their ethnic groups although it is not necessarily true. He is familiar with the areas he kills in, and feels comfortable enough to take his time in doing what he wants, or needs to do. He's probably had some history of either stalking, breaking and entering; he's probably even been arrested for exposing himself. He is escalating. If we don't find him soon, it's only going to get worse, in terms of what he does to his victims, and the time between kills." Having given them his ideas, George smiled and left.