Cardinality
Summary: A serial killer is stalking the citizens of Las Vegas. Started out as a case file but the G/S aspect demanded equal representation. This is the edited version for this site. The complete version can be found at my web site.
Rating: R for subject matter
A/N: No real spoilers. Many thanks to Burked for teaching me how to be a serial killer, among many other things.
Disclaimer: Obviously, I don't own anything related to CSI. If I did, certain characters would be getting more screen time – together!

"I cannot help it; in spite of myself, infinity torments me." – Alfred de Musset

Chapter 10

"Is Brass getting the warrant?" Catherine asked impatiently as they walked down the hallway towards Sara's apartment. The area hadn't been sealed off, there were no uniformed officers on the scene. Time was wasting; the sooner they could process her place, the better their odds of catching the killer.

"We don't need one," Grissom said shortly, stopping in front of the door and staring at it intently.

"I know she's not a suspect, but how do you plan to get inside? It's not likely the apartment manager is going to just let us walk in without a warrant," Catherine replied softly, casting him a concerned look.

"Not a problem," he said, pulling a key chain from his pocket as he cocked his head in concentration.

Grissom kept his attention focused on Sara's door, forcing himself to remain collected. He gripped the key chain painfully as he recalled the blood rolling down her arm. It had been a pinprick – how could it have bled so much? What about internal bleeding?

Closing his eyes briefly, he fought down the rising panic. They had gotten her to the hospital safely. She was already being treated. There was nothing more he could do to help her medically. The doctors would see to that.

He had to stay calm; Sara's life could still depend on it. The killer was out there. She wouldn't be safe even if … when she survived the poisoning. Not until the bastard that did this to her was gone.

Right now, his responsibility was to catch whoever had done this to her. To do that, he had to stay focused and do his job. He could do that; he could do the job. After all, it's all he had done for most of his life.

It was all he had ever let be part of his life.

Flexing his hand around the key chain, he examined the floor in front on her apartment, then turned his attention to the doorframe. Treat this like any other case. Grissom considered the fact that his effort was probably wasted on Catherine; she had known him too well and for too long to fall for his forced indifference.

"Since when have you had a key to Sara's apartment?" Catherine asked Grissom incredulously.

"Since right before we left the lab," he replied tersely, turning his head to the right to look down the hallway.

"You stole her keys?"

"Borrowed."

"I damn well hope so. You're telling her if you didn't."

"This counts as exigent circumstances."

The catch in his voice had barely been noticeable, but it was enough to worry Catherine. Exigent circumstances allowed them to bypass certain regulations, but only if someone's life was in imminent danger. "She'll be fine, Gil," she offered reassuringly.

Grissom bit back his response. She couldn't know if Sara would recover. There were still too many things that could go wrong.

Instead, he walked a few steps away, turning his head to take in the rest of the hallway. After a moment, he returned and knelt down in front of the door, examining the knob closely. Reaching over, he opened his kit and pulled out a pair of gloves.

"What did you find?"

"Nothing, yet."

"Gil?"

"The killer followed a timetable," he said, letting out a long breath. "He waited approximately 30 hours after he poisoned the victims to come back and kill them."

"You think the killer came back for Sara?" Catherine asked, donning her own gloves as Grissom began dusting the knob.

"I don't know. If he followed Max, he would have know he had gone to the doctor's office and then the hospital. That's too open, too dangerous. He couldn't have gotten to him there. The killer may have decided to go after Sara at that point. But he wouldn't have known she was working a double-shift."

"Or he was after Sara the entire time," she said, giving her friend a pointed look. "Sorry, but we have to consider that possibility."

"I know," he sighed, carefully lifting prints from the front, sides and back of the knob. Once he was done, he opened the door. "You start in the kitchen. Food, drinks, condiments, trash."

After Catherine went inside, he closed the door again, trying to think like the killer. Standing up, he turned his attention back to the hallway. No one had noticed their presence yet.

All the victims had been killed in a location where it was unlikely they'd be discovered. Wallace never worked on weekends, and stayed home the entire time. Smith was the only guard at the warehouse complex. Wilson came in hours before the other staff at the drive-in.

Brandenburg had a full-time secretary who screened all his visitors. Sara slept during the day, when most of the other apartment complex residents would be at school or work. She would have been the logical choice Grissom admitted to himself.

She's in there alone. She didn't open the door after he knocked. Was she asleep? Had she already started to bleed out? Can I force the door? Can I pick the lock? Try looking in the peephole.

Grissom held his gloved hands up on either side of the peephole, but not touching the wood. Breaking out his Red Creeper, he started lightly dusting the vertical surface of the door. Smudges from what were probably knuckles showed on several locations. Working downward, he was rewarded with handprints at a few locations.

After carefully lifting all of the prints, he meticulously labeled everything. The bastard wasn't going to get away because of a sloppy work. Heading inside, he saw Catherine putting a few containers into a brown paper sack on the counter.

"Sara wasn't kidding about not liking to cook," she said, pointing to a few bags. "There's not much selection of anything in the place. It's all here."

A feeling of sadness came over Grissom as he checked the sparse supplies in one of the bags. It seemed so meager. Tea, coffee, sugar, bread, peanut butter, cereal. She couldn't have had people over on a regular basis. How lonely was she?

"Make sure everything is labeled properly," Grissom said suddenly, turning to check out the rest of the small apartment. A quick scan of the living area showed there weren't any empty carryout containers in there. Not surprising; Sara was too neat. "And don't forget the trash."

"Already done."

Grissom turned his attention to the shelves, freezing as the beam of his flashlight hit the walls. Blood-red walls. That could have been Sara's blood, describing some perverted mathematical relationship.

Giving his head a shake, he walked towards the bathroom. The trashcan in there held little – an empty tube of toothpaste, a few tissues, and some cotton swabs. Making his way into her bedroom, Grissom stopped as he swung his light across the area.

Despite all her neatness, Sara's bedroom was a surprise. The bed was rumpled, the pillows splayed haphazardly across it. A pile of laundry sat in the corner, waiting to be done. A lone sock rested on the closet door handle for some reason.

It reminded him of a teenager's room – a place where they could express their true selves. For all her outward order, she kept her bedroom disorganized, relaxed. The thought of Sara sprawled on the bed, pulling the covers over her head, wanting to sleep a few more minutes made him smile.

The thought of her smile directed at him made his heart race.

He drew a deep breath as the realization hit him - this was Sara's apartment. This was her home. He was here to process it. She should have been safe here, her refuge from all the nightmares they dealt with in their job. Instead, it may have been the site where she was poisoned.

His hand shook as he traced a gloved finger down the sheets, realizing it was the only time he'd ever have a chance to touch them. Why had he rejected her? This never should have happened to her. He liked to cook; she wouldn't have been exposed to poisoned food.

This was all his fault.

He'd been so damned afraid to let her in, and now she was in the hospital. She could die. A light blow to the head and her brain would be destroyed before the doctors had a chance to react. He'd never have the chance to tell her, to explain, to apologize.

Sara was too young to die. She deserved so much more. What had she experienced? He'd held her back; he never would commit to her, but he never let her free. He'd hurt her so many times, but it seemed so mild compared to the pain he'd felt internally.

Never again. If she only got better, he'd see to it that she had the chance to be happy.

No matter what it took.

No matter who it took.

"Don't even think of breaking out the ALS," Catherine said hotly as she entered the room. The jerk was checking her sheets? Of all the times for his damn jealousy to make an appearance.

"I don't care if, if she's involved," he croaked, causing her to start. When he turned around, the intensity of his gaze overwhelmed her.

"As long as she lives, Catherine, I don't give a damn about anything else! I don't care if she hates me, or if she never speaks to me again, just so long as she lives."

"Hey, come on, Gil. She's going to be okay. Warfarin poisoning is treatable. Come on," she said, leading him out of the room, and directing him to the couch. She knelt before him, resting a hand reassuringly on his knee. This had to be hell on him. If Sara didn't recover, she doubted Grissom would ever get over it.

"Look, why don't I go grab her some clothes? Those hospital gowns are a bitch. You know that. Sit here. I'll be back in a minute."

Grissom sat morosely on the couch, listening as Catherine rooted through Sara's closet and dresser. A humorless smile formed. He finally figured out what to do about 'this', and it really was too late.

He'd hurt her so many times, and now he nearly let her get killed. There could still be lasting problems from the poisoning. If it hadn't been obvious to Sara before, this had to make it crystal clear. She was better off without him.

Things were going to be different from now on, Grissom resolved. He wanted her to be happy. It was out of his ability to give that to her directly, but he'd no longer stand in her way. And he would make sure she had the safety to pursue that happiness.

"I'm going to start taking the evidence down," he called out, his determination growing.

He had a job to do. It was all he had.

After arriving back at the lab, Grissom directed Catherine to log the evidence while he checked the various departments for progress. Knowing the A/V techs wouldn't have had time to correlate all the tapes yet, he headed first to DNA.

"Two things," Greg said immediately, jumping off his stool when Grissom walked in. "The DNA results are back on the brush. There were four sets. The first three match the three blood types taken from the writing at the scenes. I've got the fourth in CODIS, but no hits have come up yet. It is from a male."

Grissom nodded. It wasn't surprising. The killer couldn't wield the brush wearing the heavy gloves he'd evidently worn. There had been plenty of opportunity for epithelials to transfer to the handle.

"What else?"

"Definitely warfarin. I ran the mass spec on that blood sample you brought."

Taking the printout, he raised a quizzical eyebrow at the lab tech. While the GS mass spectrometer was faster than a tox screen, it would also show every chemical in her blood. Isolating the warfarin from all the other compounds in a few hours was no small feat.

"I want to help," Greg offered in explanation. "It's Sara."

"How does this concentration compare to the other victims?" Grissom asked, already knowing the answer as he turned his attention to the paper. The other victims had enough to kill them, but their levels were lower than Sara's.

"Much higher," Greg said, his voice dropping to a near-whisper. "Why would the killer up the dosage so much?"

Grissom cocked his head and darted his eyes to the younger man. His concern for Sara was obvious. In the past, he'd considered the lab tech's flirting with her to be a youthful folly. Watching him now, Grissom began to wonder if Greg had been serious in his attentions, only to have them go unrequited.

He could relate. Greg could use a distraction to help him focus.

"Why don't you tell me?"

Greg's eyebrows shot up in surprise. Seeing that Grissom wasn't joking, he quickly reviewed all he could remember about the case, shifting nervously from foot to foot.

"Relax, Greg. I'm not going to grade you."

"There were two victims this time," he sputtered, hating to use the term to describe Sara. "The killer wanted to make sure there was enough poison for both of them."

"If he was going after both of them. Only one may have been the target; the other could have been accidental."

"He didn't know Sara's a vegetarian," Greg offered after a minute. "Probably, anyway. He had to poison everything to make sure whoever was the target got poisoned."

"That would explain how they both got poisoned, but not the concentrations."

Greg closed his eyes, trying to think of any new angles. He opened his eyes when Grissom laid a reassuring hand on his shoulder.

"The last victim fought back. He didn't die quick enough. Maybe the killer wasn't taking any chances this time, and upped the dosage, especially considering how big Max is. Or maybe the killer mistakenly thought warfarin toxicity depends on body mass. Or maybe it was accidental."

"Don't try to guess why the killer does something," Greg sighed, nodding his head.

"'For every problem, there exists a simple and elegant solution that is completely wrong.' There are a lot of possible reasons, Greg. That's the danger of working theories, rather than evidence. You start looking for things that support your theory."

"Right," he said sheepishly.

"Come on," Grissom said, nodding towards the door as he walked out and headed towards the Print Lab.

"Jacqui, we've brought in all the food from Sara's place. Start with the carryout containers. See if you can find any prints. When you're done with that, send samples to Tox to check for warfarin. Greg, the containers are probably waxed, but see if you can get any DNA."

"Right," he said, trying to sound upbeat. The wax used would be petroleum-based, a substance that could destroy DNA evidence. The odds he would find anything useful were slim.

Grissom headed out into the hallway. Tox wouldn't have time to have finished the screen on Sara's blood, but they already knew it was warfarin.

"Dr. Grissom!"

Turning, he found Judy walking up to him quickly, a nervous expression on her face.

"This came for you," she said, handing him a letter.

"Thanks," he said absentmindedly, deciding to talk to Al. He wanted an honest assessment of Sara's condition. Grissom stopped suddenly when he caught the return address: Dr. G-M Brandenburg.

Heading to his office, he closed the door before taking a seat. Opening the envelope, he took out the letter and quickly scanned it. The first part was a simple apology from Brandenburg for his behavior in the Layout Room the other night.

That was enough to make Grissom to purse his lips. It was the end that made him wince.

"However, I refuse to apologize for being concerned about Sara's well-being. To be perfectly frank Dr. Grissom, I think you may be a danger to that.

"Whether you realize it or not, she has sacrificed a great deal on your behalf. Sara gave up everything – her job, her friends and her family – to come work for you. Ask yourself one thing: Have you done anything to warrant that kind of dedication?"

Grissom dropped the letter as he ran his hands over his temples. The last thing he needed was his shortcomings pointed out by that overgrown … He turned around to stare at his office shelf.

Who was he to judge? The thought of apologizing to the mathematician had never crossed his mind. The younger man definitely had better social skills, and he seemed sincere in his concern for Sara. The others all liked him. Brandenburg and Sara were closer in age. Maybe she could be happy with him. She seemed to like the man.

The knock on his door gave him an excuse not to finish the letter. Poking her head in, Catherine held the small gym bag in one hand.

"You better head over to the hospital soon, or you won't have a chance to talk to Sara. Visiting hours are going to be over soon."

"You go," he said distractedly.

"Gil," she said gently, walking in and closing the door behind her. "Trust me. It'll mean more to Sara if you go."

He gave her a brief, disbelieving look "There's too much work that needs to be done."

"Like what? It'll take hours before Tox can get anything back on the samples. Jacqui's busy printing what we brought in. That's going to take time, and the guy's aren't back yet from Max's."

"There has to be a way to connect the victims," he began.

"Go! She doesn't have any family in the area, and you know they're going to restrict her visitors as long as she's under protection. This has to be scary for her, and she's alone. Dammit, Gil, try thinking about her."

"I do all the time," he said softly. Getting up from the desk, he took the bag. "Page me if anything comes in."

Grissom put on a smile after he was cleared by the police officer guarding her door, wanting to cheer Sara up. Knocking lightly as he pushed opened the door, his smile disappeared as he walked in. Was this the right room?

"Hey, I was wondering if you'd make it tonight," the body on the bed said, looking up after wiping at her mouth with a tissue and throwing it away.

He blinked. That was Sara's voice. Grissom felt the blush. He'd promised her that he'd be back, but he'd nearly forgotten.

Making his way across the room slowly, he stared her in confusion. The doctors were treating her. She should be getting better. This couldn't be better.

Sara's left arm was propped on a stack of pillows, the entire thing swollen grotesquely. Angry black-and-purple streaks stood in stark contrast against her pale skin on both arms and hands. Several gauze bandages dotted her arms, reddish circles soaking through the multiple layers of cotton.

A single IV of blood remained hooked to her right hand. A transfusion – that wasn't a good sign.

"It's not contagious," she said lightly when he stayed away.

Grissom took a few steps to stand at the foot of her bed. It was neither fear of contagion nor disgust at her appearance that kept him away. It was shame. He meant to cheer her up, but he hadn't managed to say a thing since he came in.

"I guess I look as bad as I thought," she said dryly, holding another tissue to her mouth. When he made no move to answer, she gave him a worried look. Sara knew she looked like hell, but Grissom seemed on the verge of shock.

"Could you hand me the water?" she asked softly, pointing to a cup sitting beside the bed.

Her request was enough to get him to react. Setting the bag on a chair, he took the water and sat on the edge of the bed. Holding the cup out, Grissom's eyes widened as he saw the ugly bruise on her right temple.

"What happened, sweetheart?" he asked nervously, reaching one hand to brush her hair back tenderly.

"Oh, that? Nothing," she said, taking the cup. He didn't seem aware he'd used the endearment. "I got bored and was leaning my head against my hand. Not a good thing when you bruise easily. I'm okay, Grissom."

"Did the doctors check that out?"

"Yeah. It's just a bruise. My brain isn't getting squashed," she said, wiping her mouth before taking another sip.

A flash of red caught his attention Grissom blanched when he looked into trashcan, seeing the pile of blood-soaked material in it.

"Gums are bleeding. I hate spit," she sighed. Seeing his eyes dart back to her temple, she reached out to gingerly touch his hand.

Grissom looked down at her touch – the swelling and the bruising from the IV affecting her entire hand. He couldn't imagine how painful that must be.

"It looks worse than it is," she said, stroking her fingers lightly over the back of his hand, surprised when she felt his tremor. They locked gazes for a long moment before Sara broke contact. She was used to brief flashes of intensity in his eyes, but the sustained depth of emotion he allowed her to see was unnerving.

"How do you feel?" he asked softly, feeling embarrassed that she was trying to lift his spirits. What had he done to deserve this dedication?

"Like a grape that went through the wine press. Guess I look like one, too."

"You're beautiful," he said lowly, surprising both of them. He cleared his throat and turned towards the chair. "We, Catherine that is, thought you'd like some of your things. We had to process your apartment."

"I figured as much. Max and I got sick at the same time; makes sense we were poisoned at the same time," she said, looking away embarrassed. Before he could apologize for violating her privacy, she flashed him a grin. "The place is usually neater than that. I'm little behind in my laundry."

"Don't worry about it," he said quietly, his hand reaching out of its own accord to brush her hair again. "Do you want me to get a nurse to help you change?"

"Not yet. Once that thing's empty, I get to take a shower," she said, nodding at the IV.

Sara tilted her head as she watched Grissom stare at it in morbid fascination. He was scared; he may not be saying anything, but the emotion was clear in his eyes. She would have sworn he seemed guilty, but that made no sense.

"Maybe it's just me," Sara stated, waiting until Grissom met her eyes. "But it seems pretty twisted to keep sticking needles in someone with a clotting problem. I look like I got attacked by a rabid porcupine."

Scooting up gingerly, she grimaced slightly, giving Grissom a reassuring smile, but he didn't return it.

"How are you?" he asked, his voice soft, but still carrying his seriousness.

"I've got a little bit of bleeding in the digestive tract. It's not severe. My gums are bleeding," she said, holding up the tissue to her mouth. "And that's more disgusting than anything else. I hurt like hell, but they won't give me any aspirin."

Grissom snapped his head up to see her teasing look, wondering how she could joke at a time like this. Did she need to? Maybe Catherine was right; maybe this was scaring her. It had him frightened.

"The last thing you need is something that'll thin your blood," he said in mock-severity.

"That's getting better, too. They stopped the IV vitamin K treatments and switched to shots," she said, pointing to the bandages on her arms. "My INR is down to eleven. They seemed happy about that."

"It was twenty three," he said, looking away so she wouldn't see the look of relief that came over his face.

"What's normal?"

"One," he finally responded, but not until she fixed him with a steely glare.

"Oh. Well, the doctor doubts I can go home tomorrow. Maybe the day after."

"You're not fighting them?" he asked, trying to sound teasing. They were going to let her home soon. Good. That had to be good.

But the killer was still after her.

"The bathroom's closer to the bed here," she said, giving him a bashful look.

"Your stomach will settle once the warfarin's out of your system," he replied, trying to sound encouraging.

"I hope so," she said with a disgusted sigh. "I hate being sick."

"So I noticed."

"Thanks for calling my parents," she said after a minute.

"I promised I would," he said, trying not to sound defensive. He said he'd do it. Didn't she trust him with such a simple thing? He really had blown this.

"Yeah, but I know how busy things can get at the lab. I appreciate it," she said, wondering what had caused his mood swing.

"When will they be here?" he asked, grateful that she wouldn't be alone.

"I told them not to come. I don't want them around until the Pied Piper is caught," she said with a shrug. "Hippies. They'd probably invite him in for coffee and warfarin if he showed up at my apartment. Try to talk to him, give him a hug."

"Pied Piper?" he asked, trying to keep the disappointment out of his voice.

"That's what they're calling the killer on the news. They found out it he's using warfarin and figured it was rat poison."

"Oh," Grissom said, trying to understand why the media insisted on giving bizarre names to cases. He gave her a smile, hoping it seemed authentic. He'd failed to cheer her up; she had done more to make him feel better.

The very least he should do was apologize to her. For everything. She deserved to know the truth, that none of this had been her fault. As he tried to figure out where to begin, a nurse entered the room, telling him he had to leave.

"I'll be back tomorrow," he promised. "Call me if you need anything."

"Thanks," she said, watching him curiously as he left.

Back at the lab, Grissom found Nick and Warrick had returned from Brandenburg's house. Jacqui had already examined all the carryout packages, lifting what prints she could find. She'd moved onto the other containers gathered from their homes.

In the Tox Lab, technicians had set up rows of samples. Each sample was soaking in distilled water so any residual warfarin would dissolve. The samples still needed to be chilled, run through the centrifuge and decanted before they could be run through the GS mass spectrometer. It would be a few more hours before the first batch of results came in.

Greg was in the process of swabbing the paper sacks from Sara's trashcan. They would have a better chance of having usable DNA than the waxed containers or wrappers, but even that was a stretch.

Brass had started interviewing residents of Sara's apartment complex, seeing if anyone had seen anything unusual. Archie had rounded up the last of the television tapes and was examining them.

Heading into the break room, Grissom found his team – minus one – watching him carefully. This was the time shift normally started, and they had been here for hours. He had never made it home today.

"How's Sara?" Nick asked, sliding a cup of coffee over to Grissom.

"She's responding," he said softly.

"What does that mean?"

Grissom turned to look at Catherine and then the others. Several people were watching from the doorway, their expressions cautious.

"She's bleeding internally, but not severely. They have her on a transfusion. Her INR is down to eleven. Her arm is pretty messed up. She won't be able to go home for at least another day. I got chased out by the nursing staff before I could ask any more questions," he said, his tone clearly indicating he wasn't going to say any more.

Once the lab staff returned to their jobs, Grissom gave his team an appraising look.

"We are not going to screw this one up. Sara, and Brandenburg, aren't safe until the killer is caught. What did you find in the trash from the drive-in?" he asked, turning to stare at Warrick.

"Nothing. We tested every container in there. No traces of warfarin on anything."

"And nothing from the victim's house, either," Catherine added.

"Dammit," Nick swore softly. "Is he going to back off them now that he failed? Or is he going to try again?"

"I say we catch him before he gets a chance," Catherine said.

Grissom was in front of the clear board in the Layout Room, examining the pieces they knew about the killer. The victims followed no obvious pattern. It seemed they were picked based on opportunity, rather than by physical characteristics.

Someone knew enough about all the victims to know when to administer the warfarin so they'd be alone thirty hours later. He knew them well enough that they felt safe taking either food or drink from him and consuming it.

Sara was the exception, and that could be explained by the killer not really knowing her work schedule. If he had been following either her or Brandenburg from the theater, he wouldn't have a clear idea what her schedule was; she'd pulled too many doubles.

The vibration of his pager ruined his concentration. A 'nine-one-one' from Tox sent him rushing down the hallway, his team joining him from all directions.

"We found warfarin on the wrappers from the deli. Both from the sandwiches and the pickles," the tech called out excitedly as they entered the room.

With Brass in the lead, the police stormed into the deli, startling the manager and crew that was closing up for the night.

"We have a warrant," the detective yelled, motioning for the workers to head into a corner.

"What's going on?" the manager demanded.

"The day before yesterday. You received a phone order for two pastrami sandwiches on rye and an egg salad on wheat to be delivered to an apartment complex down the street."

"Right. That was the order to Sara's place."

"You seem to recall that pretty easily," Grissom stated harshly.

"She's a regular. And that good-for-nothing delivery guy I just hired never returned after he dropped it off."

"I'll get us another warrant," Brass said, pulling out his cell phone.

"Catherine, you and Warrick process this place. The owner said the delivery guy, a new one, never returned from Sara's apartment. Brass, Nick and I will go there once we get the warrant. Make sure you check everything here."

"Las Vegas Police! Open up!"

Brass nodded to the officers with the battering ram, who quickly broke through the thin door of the rundown house. The team of police swept into the room, while another team guarded the back exit. After a series of "Clears" echoed through the house, Brass lowered his weapon, nodding to the two CSIs to follow him into the house.

"Dammit."

The police captain's soft swearing caught the attention of his colleagues. Swinging their lights around they walked over to the card table in the far corner of the room. Sitting on it were a mortar and pestle, traces of a white powder in the bottom.

The rest of the surface was covered in news clippings of the killings, photocopies of mathematical texts and digital photos of Sara.

TBC