Brownian Motion
By OughtaKnowBetter
Obligatory disclaimer: some day, when the statute of limitations on intellectual property runs out, they'll be mine!
A/N: many, many thanks to my beta's FraidyCat and Alice I. Any mistakes are mine, for not listening to their good sense. A few readers may remember a certain FBI forensics researcher from the fanfic: "Brightest Crayon". Some of you even made my day by requesting a return performance—your request has been granted, with my heartfelt gratitude to those of you who took the time to let me know that you enjoyed my efforts.
"Brownian motion." Dr. Charles Eppes adjusted the protective goggles over his eyes, ignoring the dark curls that dropped haphazardly over the plastic lenses. Likewise ignored was the giggling of a few freshman girls—and one equally young boy—who had selected this particular course for two reasons: one, it fulfilled the mandatory math requirement toward graduation with a liberal arts degree and two, the professor made Dr. McDreamy look about as romantic as oatmeal.
Charlie Eppes was oblivious. The problem in front of him was far more interesting and where math and science were concerned, the building could be on fire and Charlie wouldn't notice until his experiment exploded in front of him, whereupon Dr. Eppes would then start to calculate the heat co-efficient of the blaze as well as the patterns of ventilation which would alternately stoke and direct the fire.
Not pertinent. Today's lecture was on Brownian motion, a phenomenon well known to physicists and scientists in general: Professor Eppes swung into the verbal portion of his demonstration.
"Consider the apparently random nature of Brownian motion," he told the class. He indicated the large fish tank in front of him. The tank was filled with water, and nothing else. Sunlight shone through the far windows of the classroom, causing the dust motes to sparkle above the still water in the tank. The class, well-used to Dr. Eppes's predilection for things that go boom, remained in their seats at a safe distance. "When we place a single drop of a foreign substance into water, we can see how it disperses quickly." Using an eye-dropper, he plopped a large drop of dark colored liquid into the tank. Within seconds the liquid faded and vanished. "For those of you—and I will assume that this is 100 percent of the class—who have taken high school physics, this is a classic model of Brownian motion. The molecules go from a high concentration in one spot to a homeostatic equilibrium so that the molecules are evenly distributed throughout the solution. Of course, the parts per million are so low that we can't see any of the dye; the only way we know that it's there is that we saw the drop being added.
"Now let's try adding a larger concentration, something that we have a better chance of seeing under technologically primitive conditions, otherwise known as 'with the naked eye'." Professor Eppes poured in a large beaker-full of the same dye. The class, knowing what was coming, watching with varying levels of interest. The more devious ones, suspecting that 'class participation' might figure prominently in their grades, tried to appear intrigued.
It was tough. The scarlet red dye slowly meandered a new path through the clear water in the tank, taking far too long to disappear for minds more accustomed to the rapid maneuvers of War Craft III online.
Not for Dr. Eppes. He peered intently at the display, changing position once to better observe the phenomenon.
"We assume that this motion is random," he finally said, ignoring the collective sigh of relief from the various freshman and the few left-over sophomores who had wrongly thought that they'd be able to avoid taking first year calculus. "In fact, it is not. It is the result of the molecules of the dye being acted upon by the molecules of the water. Each bumps up against each other and causes a minute change in direction. Theoretically we could calculate the trajectory of the desired molecule, if we had sufficient information about the individual molecules of water acting upon the dye. Unfortunately, we don't."
His class, judging by the expressions on their faces, didn't think it unfortunate at all. They had each experienced a moment of mortal terror that their final grade might be based upon the supposition that they were capable of churning out the aforementioned calculations. The more devious ones were already half way through deciding which senior math student might be enticed or blackmailed into an intense tutoring session.
"Now let's assume that we have a less random effect," Professor Eppes continued. He dropped a small tablet into the water, right over the greatest concentration of the dye.
The effect was immediate. Whatever the tablet was, it reacted with the water to produce a slender spray of water into the air, and the front row of students either leaned back or forward, depending on their interest in preserving the sanctity of their clothing. Most of the dye disappeared under the action of the tablet, spreading out and vanishing into the clear water, but enough remained to demonstrate the passage of the current. "This, as you can tell, will be much more easily calculated, since this reaction just introduced a clear action upon the molecules. And this, as you have suspected, is the basis for this week's homework, due Thursday. Look over Chapter Twelve, and bring in answers to questions one through four. Bonus points for anyone who creates their own problem for the class and brings in the solution proof," he called after their retreating backs.
Charlie Eppes grinned. He could always tell which ones were going to end up in his upper level courses. Those were the students with the thoughtful expressions as they left class, the ones already considering the problems that he'd set them. The others simply wanted to make their escape.
There was one other person considering the problem that Professor Eppes had set, and that person had carefully removed himself from the doorway in order to accommodate the outflow of students. Charlie grinned as he took note of the new arrival. "Hey, David. Come on in. Enjoying the lecture?"
David Sinclair shrugged, pleased. "I always enjoy your lectures, Charlie. I may not always understand them, but I enjoy them just the same. Someday I might even learn something."
Charlie snorted. "I learn something every day," he informed the FBI agent. "I learn from you, I learn from Don, I learn from my father—" He broke off, interrupting himself with a smile. "Enough about me. No, wait—more about me. What can I do for you?"
David swung into action. "Don sent me. You have some time?"
Charlie consulted his watch. "No, but if you're asking whether I want to review that latest journal entry by Isabel Kerrigrew in which she demonstrates yet again that she really has no concept of what the Eppes Convergence is about, then the answer is yes." He gathered up the short stack of papers, handing them to David before grabbing the three large text books. "Let's drop these off at my office before we go."
David relieved him of one of the texts, evening the load. "What about the fish tank? Don't you have to clean that up as well?"
"That?" Charlie's smile was bright. "I just keep telling the maintenance people that I'm running an experiment calculating the rate of water evaporation containing a foreign substance. It'll be so much easier to move when the water's gone."
Charlie didn't need David Sinclair as his own personal chauffeur, but he did need the agent to get the math professor past the large number of police and security people that swarmed around the edges of the bank that was the center of the crime scene. There were people all around: people held in by the yellow FBI tape guarding the area, people with cameras and voice recorders and note pads held back by the yellow FBI tape, and a large number of LAPD uniformed types to make sure that the flimsy yellow FBI tape had enough help to properly do its job.
There were also a hefty quantity of emergency medical types administering oxygen and various other comforting techniques to what appeared to be the previous inhabitants of the bank. Both customers and bank tellers were seated, some on the ground and others fortunate enough to find a slender space on the bumpers of the attending ambulances, some shuddering and trembling and others merely slumped against whatever was handy. One young mother clutched her son to her side, tears sliding down both faces. The boy fit tidily under her arm—pre-school age, perhaps? Charlie couldn't tell, and decided that it didn't matter. That was his brother's problem.
Charlie glanced up at the sign over the bank: First Community. He breathed a sigh of relief. The last consultancy fee that he'd received—private industry, this time, for a very substantial sum—had been deposited into another financial institution. Selfish, sure, but he didn't need that worry interfering with whatever work Don and the rest would want him to do. Any lawyer defending those perpetrators would be sure to try to disallow Charlie's calculations based on where he did his banking, never mind that the math was clearly cut and dried.
It was a large building, very bank-like in the traditional sense, with three stories worth of bricks soaring up toward the heavens. There was nothing wrong with the outside of the edifice, nothing that cleaning up of some yellow FBI tape wouldn't fix along with the removal of the ambulances. The tall glass windows were intact, and the sign hadn't even suffered from vandalism. There was a large white heart of graffiti, proclaiming that G.T. loved L.B., but the paint looked old and Charlie doubted that it had anything to do with the current crime scene. He wondered what was going on.
The inside scene was a different story. There were three or four forensics people working on the center of the tiled floor, measuring and examining what was clearly, even to Charlie's untutored eye, the aftermath of a small explosion. Black soot covered the flooring in an outward pattern, the dark particles staining the tiles in a rough circle and edging up onto the desks and stands surrounding the pattern. There were three spots of clear white where people had obviously been standing and another four where people had fallen to the floor and smudged the soot pattern.
Don broke away from where he was discussing the case with two uniformed LAPD officers to come to meet Charlie. "Charlie, glad you could help out. You're not too busy?"
"Any time, Don." Charlie kept looking around. "Bank robbery?"
"You got it. This time," Don added cryptically. He moved on to the summary. "Our perps came in and dropped a box with the soot bomb, then scrambled out of the way."
"Two bombs, right?" Charlie interrupted.
"Two?" Don was startled. "Where are you getting two from, Charlie?"
"He's right," one of the forensics people grouched, picking up a shaggy head. "There are two soot rings: concentric, Eppes. That indicated two separate explosions, one on top of the other. Didn't you see that? You've been here longer than I have, and you didn't bother to look? Don't waste my time, Eppes." A diamond stud glittered in one earlobe, and the head took notice of the consultant standing with Agents Eppes and Sinclair. "Dr. Eppes? You here? Finally?" A pink tongue glistened over moist lips. "Did you bring Dr. Fleinhardt with you?" I hope, I hope?
"Don't need him, Gatsbacher," David put in hurriedly, remembering the one and only time he'd introduced Gatsbacher to Dr. Fleinhardt. David was still collecting both jokes and angry looks from fellow agents and other forensics specialists over that episode.
Terry Gatsbacher was as much of an enigma as any forensics puzzle and perhaps more so. It started with sex: the response on the employment application said yes, please. As much and as often as possible. Is this one of the benefits offered? The application went downhill from there, and more than one supervisor wondered how Gatsbacher had ever gotten hired in the first place, muttering about revising the hiring practices that the local Human Resources department currently used.
That was only the beginning. Gatsbacher favored a look that was androgynous with clothing baggy enough to disguise any potential identifying curves or lack thereof. Goth mascara only served to engender more confusion, as did the six earrings: three in one ear, two in the other, and a third through the nose. David considered himself lucky not to need to look at the Forensics expert in the mouth, for fear of what would be pierced through the tongue. He/she/its speech was clear, however, leading David to wonder if Gatsbacher had chosen not to go that route. Even Gatsbacher's height could go either way: slightly taller than Charlie, yet shorter than Megan. It didn't help that Gatsbacher seemed to delight in the gender confusion, almost always wearing high collars that would cover over any Adam's apple or lack thereof.
The one redeeming feature that Gatsbacher possessed was the ability to decipher data from forensic evidence far beyond what any human had a right to expect. The expert seemed to spend an average of twelve hours daily on FBI tasks and no one dared to ask to what the other twelve were assigned. The chance of receiving an answer was too great. The result was a high clear rate for more than one FBI team, and so the field agents took what they could get and thanked the good Lord that Gatsbacher was on their side. An additional spiritual thank you was offered when the data that Gatsbacher produced was delivered via email and not in person.
"Do too need Fleinhardt," Gatsbacher purred, enjoying the dismay that the words put onto the faces in the FBI crowd. "This is an explosion, clearly in the realm of physics. I need Fleinhardt, not this human calculator."
Don already knew how to handle the situation. "Not this time, Gatsbacher," he said easily. "Maybe later, if this stuff is too much for you to handle."
"Too much? Too much? I'll have you know, Eppes, that I can—"
"C'mon, Charlie." Don drew both Charlie and David away from the expostulating forensics expert, moving them onto the details of the crime. Out of earshot, he suddenly grinned. "Megan would slit my throat if I let Gatsbacher anywhere near Larry."
"He's right, you know," Charlie said, totally oblivious to the sub-text in the previous conversation. "Two concentric circles, Don. That means there were two explosions, one on top of the other."
"Yeah? How do you know that Gatsbacher is a 'he'?" Don challenged.
Charles Eppes, however, had stood up to far more intensive lines of questioning by people with far greater power than his brother, and this question wasn't even accompanied by head noogies. "Whatever. The point is, two explosions. Soot bomb?"
"Right." Don swung into the actual case. "LAPD is still questioning the witnesses, but the basic story is clear. Some guy with a hat and coat walked in and dropped a box onto the floor. He runs. Everyone else takes notice, and also start to run. The bomb goes off, smoke fills the air, and then everything gets fuzzy."
Charlie nodded. "Your witnesses aren't giving you a coherent story. Everyone saw things a little bit differently."
Bombshell—literally. "Nope. They're not giving me any story at all," Don told him. "Nothing. Nada. Zilch. Big goose egg."
That didn't make sense, and Charlie said so. "Surely someone could tell you—"
"Nope," Don repeated, "and that's what's making this so puzzling, Charlie. It doesn't make sense. Each and every one of these people heard the bomb go off, started to run, and then that's the last thing they remember." He shook his head. "I'd swear that every single one of those witnesses was gassed or something, not to be able to recall anything at all, but none of the random tox screens have ever come back positive, with the exception of a couple of over-aged flower-children who never left the sixties. The bomb must have put something into the air to make them go to sleep, but even Gatsbacher's toys aren't showing anything."
"What about cameras? What did they show?"
Don grimaced. "These guys knew what they were doing. Black masks, identical dark suits. One guy tossed the bomb, and two others took out the cameras. We're getting nothing off of them."
"Anybody hurt?"
"No. Fortunately, no one. Not this time," Don added darkly.
"This time? There's been more than one?"
"Not exactly," David grumbled, getting in his two cents.
Charlie just looked at them. A pattern, here?
Don sighed. "Third robbery. This time, a bank. Previous one: high end jewelry store. First one—"
"—that we know of—" David inserted morosely.
Don accepted the correction. "—that we know of," he amended, "was a ticket office, right before the end-of-the-day receipts were tallied up. Lots of people making lots of cash purchases, so the thieves got away with a lot. Every time we're getting the same story: a smoke grenade gets rolled or dropped in, and then it's collective amnesia. Not one person can give us a description of the perps."
Charlie grinned, cracking his knuckles ostentatiously. "So we've got a pattern," he informed the pair. "Let's look at the details." He glanced around at the scene, noting the bystanders and the witnesses, all trying to make sense of what was going on. Now he frowned, realizing that the details that he needed weren't here. "How about heading over to your office?" he suggested. "I'm going to need stuff on the previous two crimes, not just this one."
Don nodded. "You got it, Buddy. Colby," he called to his team mate, "finish up here, will ya? David and I are going to take Charlie back to the office."
"Sounds good to me," Colby grinned. He retrieved another shred of the shell of the bomb, dropping it into a small plastic bag. "Enjoy riding a desk, Don."
Charlie leaned back in Don's chair, contemplating the data set out in front of him. Don and David eyed him nervously.
It was a familiar place, Don's office. Charlie had been there on many more than one occasion. It wasn't often that he'd sat in Don's chair, the one that really should have been replaced years ago except for more important budgetary constraints, but Don had moved him there two hours ago and then had gone off and come back again from his search of coffee and something more interesting than watching Charlie's hair grow as the mathematician inhaled the pertinent information. David too had trotted after his boss, swearing that he'd bring back coffee for the visiting consultant. He'd forgotten.
It was all there, all three crimes laid out in three hard charts containing separate case files. Mere manila folders weren't sufficient to enclose all the information; there was too much of it. And yet, there wasn't enough. Charlie frowned.
"Buddy?" Frowning was not what big brother Don wanted to see.
"I can try." The tone sounded doubtful, and that too was unwanted.
David voiced the straight line. "But—?"
"The pieces aren't falling together sufficiently," Charlie explained.
"Don't you have to plug in some sort of formula or something?" Don asked, squashing down the sense of desperation that was trying to bubble forth. He hadn't realized how much he was counting on Charlie for a lead. Nothing else was popping up on any of the investigations. "I mean, you only just got here. You only just started looking through the data."
Charlie shook his head. "Patterns, Don," he said, as if the phrase ought to have been enough. "That's what I do: patterns. Everything we do falls into patterns of one kind or another, and usually more than one." He pushed one of the case files away from him, almost rejecting the data. "No real patterns here. These crimes don't really look related."
"But they have to be," David protested. "Look at them, Charlie! They're all the same! The perpetrators walk into the building, drop a bomb, nobody sees them, and they walk out with the goods. It's the same M.O., every time," he added. "They even take out the cameras in the lobby, every time."
"Looks like a pattern, but not really," Charlie told him. He warmed to his subject. "Different settings, and criminals tend to stick to what they know best. They hit jewelry stores, or banks, but not both."
"Not always," Don grumbled. "Sometimes they vary their M.O."
"Even taking that into account, let's look at the number of people involved," Charlie went on. "Three people were involved with the jewelry store, and four for the ticket office. How many at the bank?" he asked ever so innocently.
Don and David looked at each other. "Six," David muttered.
"What was that? I couldn't hear you."
"Six," David said in a louder voice. "Six, Charlie."
"Six," Charlie repeated. "Not three or four. I'm going to assume that nobody's put a want ad in the classifieds, looking for hired guns."
Don scowled. "Not that I noticed."
"I'm also going on the assumption that you regularly scan the criminal version of a newspaper, looking for things such as that."
"Just keeping an eye on who's on the way up, and who's on the way down."
"Of course." Charlie dismissed that facet of the discussion as a given. "Initially, it looked like there was a pattern for discrimination: three crimes, all using smoke bombs, all eliminating the cameras as they walked into the lobby. Then the coincidences stopped. The rest is all random: different numbers of perpetrators, different types of establishments robbed. There's nothing to distinguish this from three different groups of criminals doing three different criminal acts beyond the use of the smoke bomb. Copy cat stuff. One guy gets a bright idea, and a couple of others decide to do the same thing." He hit the shut down keys on his laptop, and the machine gave a melodic chirp of dismay. "I'm sorry, Don. I can't help you. Not right now. If there are more crimes that you think are related to these, call me but at the moment there simply isn't enough data. What you've got here are a bunch of coincidences and nothing more. Several different groups are using smoke bombs as their method of getting the crowds under control, and that can be written off as a statistical outlier. Sometimes coincidences happen. There's always that one chance in a million, and you hit it lucky today. The three crimes look planned, it looks like a pattern, but when you delve into it there's nothing more to support the theorem. You just have a few different groups that are using tried and true methods for crime." He pushed down the screen to his laptop, all three of them hearing the click that put the machine to bed. He reached for its case. "I'm sorry, Don," he repeated. "Bring me more data and I'll try again."
"You mean, something that supports some kind of pattern," Don grumbled.
"Well, yes," Charlie admitted. "You don't need me to stick three pins in a map."
David automatically glanced at the map that was tacked to the wall. "One in East L.A., another in Hollywood, and the third down in Orange. Not very close."
"And not likely to generate realistic probabilities for the next target," Charlie agreed. He stood up. There was no point in prolonging the time and there were several articles that he really needed to review.
"Don! Hold up, Don!" Megan increased her stride to catch up to her boss in the hallways of the FBI building.
Don obligingly slowed. "Megan? What'cha got?"
"Not good, Don." Megan fell into step beside him. "The bank job? First Community Bank? We've got a fatality."
"Damn," Don breathed. Up to this point, there had been none. A whole bunch of scared witnesses, too scared to remember their mothers' names, but everyone had walked away from the experience with less money and a new phobia to bring to their shrink. "Who? How?"
"Prelim from the M.E. says smoke inhalation, but she's saying it with a whole lot of 'maybe'," Megan informed him. "Our victim wasn't young, wasn't sick, and should have been able to handle a little bit of smoke. He wasn't even close to the center of the explosion, which would have exposed him to a larger quantity, like a fire fighter. He got to oxygen fairly quickly, according to the records."
"So what you're saying is that there's more to this than meets the eye." Don swiftly reviewed what that meant in terms of the case, an action which didn't impede his forward progress toward his cubicle. "Well, at a minimum, this turns this thing into homicide. That's a step up from the other two." Despite Charlie's disclaimer, Don hadn't yet given up on the three different crimes being related. There was a small butterfly in his gut flying around screeching about some sort of spider web connecting the three, and that there would be more crimes committed in a similar fashion. Don would admit to more than one mistake in his career as an FBI agent, and failure to listen to his gut was one of them. His New Year's Resolution had been to not let that happen again. "What happened to the guy?"
Megan shrugged unhappily. "Not a clue; not yet, at any rate. I made the M.E. promise to finish the autopsy next so that we'd have her report by this afternoon. That was the best I could do," she added with a sigh. "The tox reports won't be back for a couple of days, even if the M.E. thinks that there was something else involved. Just between you and me," Megan confided, "I think that the M.E.'s betting on some sort of natural cause, like an aneurysm blowing under the stress. This might not be a homicide at all, just another unlucky coincidence."
"Getting tired of coincidences, Reeves," Don mock-growled. He was well aware that every member of his team felt the same way, that there should be some sort of clue that they could nab to lead them to a decent set of suspects. "Stay on it. Keep me posted."
"Right. You?"
Another sigh, this one big enough to blow the papers off the desk in the cubicle down the hall. "Director's dumping another case on us. Kowalski turned up a lead on a meth lab downtown, and the director doesn't want him blowing his cover. We get to hit the place tomorrow, at sunrise; see what we can drag in and if we can develop any leads from there."
"Gawd," Megan groaned. "You're right, Don. These three maybe-related cases are going to get pushed to the back burner." She glowered. "This means we're going to have to be here at five in the morning, for the bust?"
"Gotta love it, Reeves."
"No, I don't, Don. I don't love it one bit. It's enough to make me question my choice of career," she informed him glumly.