A/N - Sorry for the long wait. Virtual chocolates and digital hugs to Jolie Black, sevenpercent, and ThessalyMc for gently kicking my butt back on track. Your comments and reviews go a long way toward keeping it there. -GW

Mary wakes to the sounds of John finally getting ready for bed, trying to be very quiet in the bathroom brushing his teeth by the small nightlight and running the water in the sink at a trickle. The alarm clock says it's almost four a.m. He started working on his laptop at the kitchen table almost as soon as their guests left last night, and he was still at it when she came upstairs just after midnight. She didn't ask what he was doing, but it's not hard to guess that it has something to do with Sherlock. That's who he was with when she called to remind him to come home last night. She can always hear it in his voice, a quality that's something between a soldier on guard, and a little boy up to mischief. He's never asked how she always manages to suss out his Sherlock moments, and she's not sure she could explain it if he did.

But right now, it's four in the morning, and he's due at the clinic at nine o'clock for his shift. He'll barely be able to keep his eyes open, let alone do justice to his patients. Intervention is called for.

She hears him open the door, tiptoe across the carpet to his side of the bed and slide gingerly under the covers.

"John," she says softly, touching his shoulder so he rolls over to face her. She knows he can see her in the dim glow filtering through the curtains from the street lights. "What are you doing?"

"Sorry," he whispers. "Go back to sleep."

She reaches over and turns on the bedside lamp, making them both squint. "Are you working on a case?" She raises herself up on one elbow.

"Sort of." He pinches the bridge of his nose. "I stopped by to see Sherlock, and he got a call from Molly while I was there. I went along to Bart's, and he asked me to do some research for him."

She touches his cheek, and he leans into it. "You're going to fall asleep at your desk."

"Again." He smiles. "Really, I'll be fine, but I do have to meet Sherlock at eight. We're going to see Greg. I don't have to be at the clinic until ten." He yawns widely.

"Nine," she corrects him. "He's going to need you longer than that."

John shakes his head. "He only brought me along because I was there when he got the call. He'll do just as well on his own."

She hears the same disappointment that was in his voice last night when she called. He had done his best with their dinner guests, and managed to look interested and engaged, but she could tell where his mind was. Sherlock's absence is never complete. Not when they thought he was dead, and certainly not now. She appreciates that John is trying to do what he thinks she wants, but he's got it wrong. "You have to stay on the case."

He pulls back a bit and looks at her. "I have a job."

"Yes, and it can wait. You need to help Sherlock. Reschedule the five days you were going to use for our trip to Brighton. Take them now, and go work with him. I'll hand your patients off to the other doctors. No one else is out this week. It will be fine."

"What about our holiday? You were looking forward to that."

She notices that he used the past tense, and it's all the confirmation she needs. "Go to sleep, and call the clinic in the morning. I'll take care of the rest." She turns off the lamp.

John is smiling. She can hear more than see it. "Mary, have I told you lately that you are the love of my life?"

I'm one of them, she smiles to herself. "Have I told you lately that you're the best thing that's ever happened to me?" She kisses the tip of his nose. "Sweet dreams."

He's snoring softly before she's even got her pillow pushed into shape.

Sherlock opens John's email and prints the list of sixteen names. The sheer number tells him that John failed to adjust his search in response to the results he was getting, something Sherlock had done automatically and assumed John would also know to do. The list will need to be cleaned up, and he starts by crossing off the four that match his own list. He looks up the rest, and eliminates all twelve. John has neglected to filter out missing persons who are still missing, teenage runaways, and adults who have clearly disappeared of their own volition.

They started with the three murdered suspects who Molly believes are victims of her serial vigilante: Michael Hartman, William McConnell, and Owen Brandt. Their Internet search has found four women whose families believe were murdered by men the police have identified but can't prosecute. Their websites offer rewards for information that will put these unnamed men away. They're all made-to-order for Molly's serial vigilante, if he exists. And if he does, he could easily have found these same cases.

But then what? He finds cases that need justice, but how does he get the names of the suspects? The families don't have access to them, according to Lestrade. So how could a vigilante get them?

Obviously, from someone who does have access, which is not as exclusive a group as it might seem. The investigating officer would know the identity of the suspects. The desk sergeant records the names of anyone brought in for questioning, even those that aren't pursued beyond the initial interview. And the interviews themselves are recorded on both audio and video. The vigilante has to be getting the suspects names from one of those sources. The question is, how?

No, he corrects himself. Asking how the vigilante acquires the names of his targets assumes the vigilante exists, a premise based entirely on inference from a handful of potentially random cases. If anyone but Molly Hooper had come to him with this vigilante theory, he would have tossed them out of the flat. He's giving it more effort than it probably merits because he owes Molly more than he can ever repay, and not just for helping him two years ago. The hell she endured in silence because of that favor is something he's only recently begun to appreciate. A few days spent on a potentially dead end case is the very least he can do.

That's why he took her case, but it's not the reason he's sticking with it. There's the undeniable lure of getting to work a case with John again, and he recognizes the possibility that his objectivity may be affected by sentiment. If he wants to be honest, being able to spend time with John on even the flimsiest of excuses explains a lot of what he's done since he came back. The Christmas drinks party is one classic example. The excuses and opportunities are getting fewer by the day, and it won't be much longer before they're entirely gone. It's that looming inevitability that's fueling his interest in this case. It may be the last.

With that appallingly sentimental thought, he turns off the laptop and orders himself to sleep.

When Sherlock gets into the cab in front of Baker Street at eight o'clock, he finds John sipping from a container of coffee, looking a bit like death warmed over. He wordlessly hands a coffee to Sherlock and yawns.

"Long night?" This earns him the expected scowl.

"I hope it was worth it."

Sherlock nods. Probably not the ideal moment for a lesson on how to refine Internet searches. "Always."

They find Lestrade's office empty, but he comes bounding in a moment later with his own mug of coffee. Sherlock hands him the list, and the DI's expression shifts from interest to disbelief as he scans it. "I know you don't think much of our investigative abilities, but seriously? Seven murder suspects ending up murdered themselves would be pretty hard to overlook."

Sherlock resists the urge to agree with him. "Humor me."

Lestrade snorts. "Like I never do." He lays the list next to his keyboard, fingers poised over the keys for a moment before he looks up at Sherlock. "What am I looking for?"

"We're testing a hypothesis that posits the existence of a serial vigilante who finds unsolved murders to avenge by surfing websites set up by victims' loved ones. We put together the list you have there by using the criteria we believe he would use. If any of the cases on the list are still unsolved, the next step will be to narrow the field to those that also had a single suspect."

"That's a lot of ifs," Lestrade states the obvious.

"And if none of the cases fit the criteria, we'll be one step closer to disproving the hypothesis."

Lestrade puffs out a breath. "Fair enough. I'll print a summary of any unsolved cases." He starts typing.

The printer begins to hum with the first case. Lestrade glances up at Sherlock as the second, then the third, and ultimately all four names appear to meet the requirements and are printed out. Lestrade picks up the stack and hands it to Sherlock. "Okay, you have my attention. They're all unsolved, and there does seem to be a single suspect in each, all unnamed."

"Unnamed meaning what?" John asks.

"Meaning they couldn't be arrested. The notes state that the investigations have reached an impasse. That's a euphemism for 'we know who did it, but we can't prove it'. If there were no suspects, it would say so."

Sherlock scans the text. "This one," he hands one of the summaries back to Lestrade, "has a suspect listed on the website. Gerrold Wakefield. The site says he's dead."

Lestrade types the name, and reads the screen for a moment. "He's dead, all right. He was found hanging by a leather belt looped around a towel rod in the bathroom of his flat, surrounded by porn magazines. The coroner ruled it a death by misadventure. Autoerotic asphyxiation."

Sherlock frowns. "Not a homicide."

"No," Lestrade confirms, "but if your vigilante had a hand in it, he could have made it look this way pretty easily, couldn't he?"

"You think there is something to this, then?" John looks as surprised as Lestrade.

"It's worth another look, at least. Like I said, seven dead murder suspects would be pretty noteworthy. You have four already. To find the names of the three remaining suspects, you'll have to go to the investigating officers. The names would be in their personal case notes."

"You can't look up the case notes from here?" Sherlock asks, handing the summaries to John.

"We all have our own files, and they're not accessible by anyone else. That allows us to record unproved theories that don't belong in an evidence file. It's a legal consideration."

John scans the sheets and looks up at Lestrade with a slight frown. "All four were handled by the same person. DI Thomas Masters."

Sherlock looks at Lestrade. "One DI on all four. What are the odds?"

Lestrade is shaking his head. "You know him, Sherlock. Masters is the straightest guy I've ever worked with, and he's assigned to a lot of homicides because he's one of the most experienced investigators we've got. It's coincidence."

John frowns. "I've never heard of him." He looks at Sherlock. "You think he could be involved?"

"The universe is rarely so lazy. I think the fact that he's the investigating officer on all four cases needs an explanation." To Lestrade, "Is Masters in today?"

Greg picks up his phone and punches in a number. "Tom? Greg Lestrade." Pause. "Yeah, it's been awhile. Listen, I've got a couple of consultants looking into some cold cases, and they've got some questions for you, if you can spare them a few minutes." He shoots a warning look at Sherlock. "Great. Thanks. I'll send them down now." He hangs up the phone and folds his hands on the desk. "You tread lightly. I would bet my pension that you're nowhere close to the right answer here."

Sherlock gets to his feet. "Lightly. Of course."

John follows him to the door and nods at Greg. "I'll do my best," he answers Greg's questioning look.

Masters' office is identical to Lestrade's, but on the next floor down. He has the same cluster of desks just outside for the officers who report to him. All but one are currently vacant. The DS who is still at her desk glances up and nods. Masters' door is open, and it's obvious that he is not happy to see that the consultant Greg sent to him is none other than Sherlock Holmes. He stands. "I wondered why Greg didn't mention who he was sending down." His tone says he doesn't wonder anymore.

Sherlock introduces John, then steps aside so they men can shake hands.

"Dr. Watson," Masters says pleasantly. "I've heard good things about you." His glance at Sherlock is pointedly silent.

Sherlock and John take their seats in front of Masters' desk.

"We won't take up much of your time," Sherlock begins as he places the summaries on Masters' desk and gives them a push. "You were the investigating officer on these cases. We're looking for any that had a single strong suspect, but without sufficient evidence to prosecute."

Masters frowns and pulls the papers over in front of himself. He scans the names. "These all fit that description." He looks up at Sherlock. "But you already knew that."

Sherlock smiles, treading lightly as promised. "The single suspects in these cases. Would you have the names?"

Masters crosses his arms. "I remember them. They tend to stick in your head when they get away with murder." His eyes narrow. "Is that what this is about? You think I screwed up? I know you think we're all idiots, Holmes, but if you're here on some kind of witch hunt-"

"Not at all," John cuts in. "This has nothing to do with the way the cases were handled."

"Right," Masters is still looking at Sherlock. "Then what's it about?"

"You said you recall the names. Do you know if they're still alive?" Sherlock asks, watching Masters closely for a reaction.

The DI obliges with a puzzled frown. "Why?"

"Pursuing a lead." He's being deliberately cryptic, pushing a button he knows from their past encounters.

"Drop the act and tell me what you're after."

Sherlock sits back. "We're looking for a possible link to a current case." He sees John shift in his seat and give Sherlock a sidelong glance.

Masters rests his forearms on the desk and leans over them. "You never change. Fine. I'll give you the names, and no, I don't know if they're dead or alive. Why would I?"

"They may have been murdered by someone who takes exception to killers getting away with their crimes."

"And you think that 'someone' might be me?" Masters snorts. "Does Lestrade know what you're up to?" He shakes his head as he picks up a pen and notepad and starts writing. "Sod that. He knows better. And so do you." He tears off the sheet of paper and shoves it and the summaries back across the desk.

Sherlock smiles. "It's been a pleasure." He stands up and heads for the door.

John thanks Masters for his time, and follows after Sherlock.

While they wait for the lift, John clears his throat. "You two have a history, I take it?"

The lift doors open and Sherlock steps inside. He shrugs. "It was shortly after I began working with Scotland Yard. He took exception to my methods."

John smiles. "Imagine that."

Greg looks up the names Masters gave them and finds that only two are open homicides. The other two were ruled accidental, but both of those involved asphyxiation. "Sherlock, none of these fit what you said you were looking for. The homicides both had obvious defensive wounds, so the paralytic drug you thought was the murder weapon seems to be ruled out. All you have is a group of seven suspected killers who died over a six year span. I'll admit, it seems odd, but where's the link?"

Lestrade has a point. The same point Sherlock has suspected himself of avoiding. The drug link that Molly thought she had found has been only tentatively established in one case, and merely suspected in two others. Two of the seven aren't even homicides. The Internet could still be a common factor, but they already have an exception. James Anderson did not put up a website. The only mention of his wife's attack was on news sites, and very few of those. Her death was mentioned in a small single-column article on one news site. "There may not be a link."

"What?" Lestrade and John say it in unison.

"We still don't know that there's a vigilante to find." He gets up and walks to the window, needing to move but lacking the floor area for a proper pace. "Masters didn't know that these suspects were dead. Maybe suspects ending up dead isn't that unusual. Since the assumption that Hartman's murder was related to his victim's death is what got us thinking there might be a vigilante, it's obvious that we need to establish whether that assumption is correct." He looks at Lestrade. "Would you necessarily know if a suspect died after a case was no longer active?"

Lestrade frowns. "Maybe. I guess it would depend on how recent the case was. I'm not quite old enough to be reading the death notices every day, so unless they died in some spectacular way that made the papers, probably not."

"The only link we have established is that they were suspected of murder, and they're dead. We need to determine if that combination is even exceptional. If not, then there's no case." Sherlock comes back to his chair and drops into it. "So, how do we find out?"

Lestrade picks up a pencil and starts flipping it between two fingers, deep in thought for a moment. "I think I know someone who can help. Bring your paperwork." He gets up and heads for the door.

They catch up with him at the lift as he presses the button for the basement. "There's a storage room for evidence from active cases. I'm going to introduce you to the man who keeps track of it." The lift doors open, and they all get in. "Aside from the main evidence database, there's an unofficial one that's a goldmine of trivia that the sergeant has been keeping for years. If there are more dead murder suspects out there, he might be able to find them."

The doors open onto a corridor that looks very much like the one they just left. Instead of the expected bare cement walls and floors, it's brightly lit and painted. The floor is identical to the linoleum in the main part of the building. "Down here," Lestrade tells them, and heads down the hall to where it ends at a gray painted steel door marked "Evidence Locker". Lestrade swipes his entry card in the card reader to the left of the door. A green light appears, and the door unlocks with a metallic clank.

The space on the other side of the door makes no pretense of being anything but a basement. The ceiling is much higher than the corridor behind them, and overhead fluorescent lights are suspended from it on long cables. Most of the area is devoted to floor-to-ceiling ranks of metal shelves stacked with identical plastic storage boxes. A workbench on the right holds a printer and three fat binders. Two desks are placed back to back opposite the workbench, one with a computer monitor and keyboard. The other belongs to the man they're here to see.

A balding, paunchy man in his fifties stands as they enter. "Detective Inspector. What can I do for you, sir?"

Lestrade introduces them. "Sergeant Will Power, this is Sherlock Holmes and Dr. John Watson."

Sherlock lifts an eyebrow, and the sergeant chuckles. "Yeah, my mum had quite the sense of humor. My sister's name is Emily. Em Power, but she'll give you the death stare if you call her that." He grins. "But then, you've probably heard a comment or two about your own name," he tells Sherlock good naturedly. "No offense."

Sherlock smiles. "None taken."

Greg nods at Sherlock. "He'll give you the details, but I brought them down here to do some research on your computer." Emphasis on 'your' draws a nod of understanding from Power. "I'd appreciate any help you can give them."

"I'll do whatever I can, sir." He turns to Sherlock. "If you'll come with me?" He goes to the computer desk and pulls out the chair, waiting for Sherlock.

"Stop by my office when you finish up here," Greg tells Sherlock on his way out the door.

Sergeant Power sits down when Sherlock and John join him. He starts tapping keys as he talks. "I can go through the basics, and you can take it from there, if you want. I've got all the time you need, if you want me to do the searches for you. Up to you."

Sherlock walks to the opposite side of the desk so he can see the sergeant's face rather than the screen. "If you don't mind, I'd like to hear about how you came up with this unofficial gold mine."

Power stops typing and meets Sherlock's gaze. "'Unofficial' is the operative word, you do know that, right? It's not quite top secret, but close enough."

"We've been so advised," Sherlock agrees.

The sergeant looks up at John, who nods. "Okay, then. I didn't actually come up with it. The man who had this job before me did most of the groundwork. I've added to it over the past eight years. Upgrades and what not. Had some help with that from our tech guru, but mostly I just add the bits of information that look useful."

John is standing at Power's right, watching the screen. "How do you decide what to add?"

"Experience, and gut instinct. I was in the investigative end of it for a few years, and you pick up on what might come in handy later on. What I keep track of is information that isn't, strictly speaking, officially part of the record. Speculation. Unproved theories." He looks at Sherlock. "I get the impression that's the kind of thing you're after."

"Actually, yes," Sherlock agrees. "We're looking for murder suspects who became murder victims. They won't be listed as official suspects, and they won't be in the official case records, but they may be in the investigating officer's personal case notes. Do you ever see those personal notes?"

Power frowns. "Not very often, no. They worry that I might accidentally enter personal notes in the official record." He looks mildly offended. "I would never do that, of course, but I understand the concern. Could blow an entire case, if the defense got hold of it."

"You said 'not very often'. That suggests that you do see them occasionally." Sherlock passed his tolerance for small talk with the name discussion.

"Sure, sometimes. I can't recall any specific instances offhand, but if the investigator asked me to include a name, I wouldn't necessarily know that it was a suspect. Could be a witness."

"Yes, and what do you do with those names, should you be asked to record them? Is there a designated field?"

Power taps keys and points at the screen. "There's a free form field here. Fifty characters. I add notes there in a sort of abbreviated language that makes it easier for the program to find. One example of a key I've added is whether victims are found inside or outside. If inside, then what room. I started doing both of those keys a few years ago, and one of the DI's solved a case with the fact that a serial liked to leave victims in the bathroom."

Sherlock nods. "Excellent. Can you search it?"

"It takes a long time for the program to go through all that information, but sure. I just need to know what to look for."

"Any case where the victim is mentioned in the free-form field of another case. Do you think you could do that search for me?"

Power winces. "That's a bit beyond anything I've tried to do before. You might need our tech guy. He comes in twice a month to tidy things up in this database as well as the one the DI's use for their case notes. Daniel Manning. He's due in next week. I can't put you in touch with him before that without calling to get his okay. Manning's a bit of an oddball. He nearly took my head off a few months ago for giving his phone number to one of the gals from Forensics. Sorry. I can't afford to end up on the bottom of his list when I've got a problem here."

"I understand. I think we can handle this without bothering him." They'll get Manning's contact information from Lestrade and avoid giving the subject advance warning. "Would you be willing to let me try setting up the search for you?"

The sergeant hesitates. "I imagine you wouldn't ask if you didn't know what you're talking about, but if anything happened to screw this up, it would be my job. Are you sure you can do it?"

"I'm sure, but you might feel more comfortable if we get DI Lestrade's approval. Did you want to call him?"

Power purses his lips for a moment, then nods and gets up from his chair. "No need. Have at it, then."

Sherlock sits down and identifies the software. It's a fairly straightforward SQL database. "How did you code the names?"

"Last name, space, first name. The first two letters are uppercase 'NM' followed by a hyphen."

Sherlock nods. He quickly writes and tests the query that will identify and store the names in a temporary table. Then he saves it and adds an icon that will execute the script.

Power is standing behind him, looking over his shoulder. "You do know what you're doing," he says, obviously impressed. "You and Manning would get along fine."

Sherlock smiles briefly. "Click on this icon when you get ready to leave tonight. It will produce a table of names from the database that we'll use to do the next search."

"So, you don't really need Manning, then?"

"I don't think so. I may have some questions about the security and access to the database at some point, but you needn't bother him with it now."

Power smiles with relief. "That's good. And I won't mention that you've been tinkering." Power winks. "He's very protective of his baby."

Sherlock gets to his feet. "You've been very helpful, Sergeant." He gives Power his mobile number. "Please let me know in the morning if the query has finished searching. There will be a message on the screen."

"Sure thing." Power offers his hand, and Sherlock shakes it. John follows suit.

As soon as the door closes behind them, John says, "Big hands. Very firm grip."

Sherlock nods. "Same as DI Masters. And Philip Anderson. And me, for that matter."

John chuckles. "Well, all but the grip. You've got long fingers, but you're not in the same league in the bone crushing department."

Sherlock gives him a look. "Just because I don't crush bones when I shake someone's hand doesn't mean I can't."

"Yeah, well don't feel the need to demonstrate." He glances at Sherlock's hand as he presses the lift button. "Are we coming back here in the morning?"

"As soon as the sergeant calls to tell me the query is finished. I'll take the names it produced and write another query that will look specifically for pairs of cases where the murder victim in one also appears in the free-form field in the second." He waits for John to put it together.

It doesn't take him long. "And each pair of cases would represent an innocent victim, and her killer."

"Exactly."

"How many do you expect to find?"

The lift doors open on Lestrade's floor. "There should be very few, if we're right about a serial killer being responsible. If it turns out that dead murder suspects are more common than we think, then the seven we've found aren't an anomaly at all, no matter how odd it seems at first glance."

John considers this. "And if it's not unusual, that would be evidence that there's no serial killer after all."

"It would discredit one of the few indicators, yes."

"But not finding more of them wouldn't necessarily prove that we have a serial killer, either." John looks mildly disgruntled.

"You're catching on." From John's frown, Sherlock realizes this didn't come across as a compliment. "If we can get this tech guru's address from Lestrade, can you go with me to interview him? Or do you have more dinner plans?"

The frown melts. "I'm all yours for the next five days, in fact. Mary insisted. She gave up a five day holiday in Brighton so I'd have time to work with you."

John clearly sees this as proof of Mary's generosity, but it feels more like charity. Or pity. It hasn't escaped Sherlock's notice that Molly and Lestrade, and now Mary, have all seemed a bit overly pleased to see John with him. He wonders if they share his sense that his time with John is ending. He pushes the thought away, and the twinge of loss along with it. "Excellent. I'll keep you busy." He finds himself looking forward to proving the existence of a serial killer with a totally inappropriate sense of pleasure, and feeling not one whit of guilt.

Lestrade is talking on his phone when they enter, and he gestures for them to wait. He ends the call a moment later, and sits back. "Got it solved?"

"Daniel Manning. I need to contact him."

"Who the hell is Daniel Manning?"

"According to Sergeant Power, he's the computer consultant who does the maintenance on all of the databases, including the main database and the ones the DIs use for their personal files."

Lestrade's face lights with recognition. "Oh, okay. Dan the Man. Yeah, he's one the consultants they hired after the staff cut backs. Let six people go, and then hire the same number of consultants at twice the price. What kind of sense does that make?"

John, who has done locum work himself, seems to take umbrage. "Consultants cost less because there are no benefits involved. And you can dismiss them without cause. It's the way things are done now."

Greg glances up at John. "Yeah, maybe. It's all a little too cold blooded for my taste." He turns to his computer. "His phone number will be listed, but I'll have to contact personnel to get his address, if you need it."

"I need the address," Sherlock confirms. "And I don't want him to know we're coming."

Greg stops typing and picks up the phone. It takes a bit of persuasion to pry the home address out of the personnel department, and Sherlock is pleased to hear Lestrade caution the person he's talking to that this is a confidential inquiry and there is to be no mention of the request to Manning.

Greg hands Sherlock the Post-it note that he used to jot down the information. "He's in West Hampstead."

Sherlock consults his internal map and comes up with an approximate 25 minute commute at this time of day. IT consultants spend a lot of time at home, and the chances are good that they'll catch him there at the lunch hour. That allows time for a few more questions. "What made Sergeant Power trade investigating crimes for cataloging evidence?"

Greg studies him for a moment. "Didn't I hear you say 'this is not the work of a disgruntled policeman'?"

"You're assuming he's a suspect because I want to know more about him?"

Greg sits back hard enough to rock his chair. "Are you saying you're just curious?" His expression says how likely he finds that possibility.

John's raised eyebrow echoes Greg's question.

Sherlock looks from John to Lestrade, hoping for a spark of understanding without the need to lead them to the obvious. He exhales, not quite a sigh of exasperation, but close enough. "We had to go directly to the investigating officer to get the names of the suspects. They're not listed anywhere outside Scotland Yard. It seems fairly obvious that Scotland Yard has to be where the vigilante is getting them, too. Either the information is being deliberately leaked, or it's being stolen."

Greg gets up and closes the door, then leans against it with his arms folded over his chest. "This is sounding more and more like a copper who's had his fill of the lawyers letting the guilty off the hook. There's not a one of us who hasn't had the thought, I can tell you that. Get a group of us together at the right time with a few pints, and you'll hear that message loud and clear. I've never known of anyone acting on it, but the urge is there more often than we'd like to admit. If that's what's going on here, I can't leave it to you."

Sherlock gives Lestrade an look. "If you bring in an official investigation, you'll never find him. This has probably been going on for longer than we know, and whoever is responsible clearly knows how to avoid detection. If you get his guard up, he'll close down and disappear. No one else will be killed, but he'll never pay for the murders he's already committed. He knows how to work the system. He hates it, but he knows how to use it."

Lestrade uncrosses his arms. "Then you do believe it's one of us?"

"No, but it is someone who has access to your files. That's why I want to start with Manning. I want to see how secure he thinks his system is."

Lestrade returns to his desk, and Sherlock sits back down in his chair.

"Now, tell me how Power ended up in his current job."

Lestrade presses his lips together in a frown. "Eight years ago, he was the investigating officer on a case where a woman claimed she was being stalked by a man she had dated years before. She said he was calling her in the middle of the night, following her home from work. Showing up at pubs when she was out with friends. There was no proof. Her friends never saw the guy. There was no record of the phone calls she claimed he was making. She had a history of emotional problems, and the man she accused of stalking her was as normal as they come. Recently married. Good job. Power talked to him, and it seemed pretty clear that the woman was imagining it all." Greg takes a breath and huffs it out. "No proof until she called 999 in a blind panic one night and said he was there at her flat, threatening her with a knife. The police arrived in time to see him running down the street, covered in her blood."

John winces. "There was nothing he could have done, but he thought it was his fault."

Greg nods. "He was off work for three months after that. When he came back, they put him in the evidence room, and he's been there ever since."

"Was the man convicted?" John asks.

"Yes. He's in prison for the rest of his life."

Sherlock flicks a bit of lint from his sleeve. "Then Power has nothing to avenge. The killer has been punished."

John frowns. "But it might make him very sensitive to other killers getting away with it."

Lestrade seems to agree. "It was enough to make him stop working in the field. I don't think you can eliminate him ."

Sherlock exhales his impatience. "Until we have more data, everyone at Scotland Yard is a potential source, and anyone they talk to is a potential suspect."

"You're sure you don't want this opened as an official investigation?" Lestrade clearly disagrees.

Sherlock and John are halfway to the door. Sherlock turns. "We don't know that we have a vigilante, but if we do, that is the surest way to drive him underground where you'll never find him." However, Lestrade's concern is legitimate. "You will have plausible deniability, if this turns into an internal matter. We will not involve you in any further speculation until we have something solid. Agreed?"

Lestrade sighs heavily. He nods. "This is the most convoluted mess I've ever run across, and you're not making it any clearer. That's a first, by the way. You investigating a case with so many holes. What's the attraction?"

"I'm bored." The lie comes easily, and he walks out of the office before Lestrade can respond.

The cab ride to Hampstead takes twice as long as Sherlock expects because of a lorry crash that holds them up for thirty minutes. By the time the cab pulls up in front of Manning's address, it's nearly one in the afternoon.

It takes another few minutes to find the entrance to the flat down a narrow passage between two converted Georgian houses. Manning's studio is on the ground floor hidden from the street by a large trellis that's still covered in unpruned and withered rose vines.

Sherlock knocks sharply on the door. A moment later, it's opened by a man in his early thirties who is about John's height. His thin face, ginger hair, and black horn-rimmed spectacles make him look shy and studious. His deep brown eyes widen as he looks up at Sherlock, and his mouth hangs open in surprise.

"Daniel Manning?" Sherlock inquires politely. "I'm Sh-"

"Oh my gosh, I know who you are," Manning cuts him off, then looks at John. His mouth closes around a huge smile. "Sherlock Holmes. And Dr. Watson." He looks back at Sherlock, clearly delighted.

John tries unsuccessfully to smother a grin. "It's nice to meet you. May we come in?"

"What? Oh, I'm an idiot. Of course." He steps back and holds the door wide.

Sherlock steps through first, followed by John, who nearly bumps into his back when Sherlock stops just a few feet inside. There's literally nowhere to go. The room is small to begin with, and the clutter on every surface has spilled onto the floor. It's all books and papers, stacked and piled and falling over into untidy heaps. Not dirty, going by the absence of odor, but unbelievably crammed to the rafters.

"I'm sorry for the mess," Manning says as he manages to come in far enough to close the door behind them. "I never seem to notice it until somebody drops by." He edges around them and starts rearranging the debris on the sofa to make a place for them to sit down. He's blushing furiously.

"Don't worry about it. We'll just stand," John tells him, glancing up at Sherlock. "I know someone else who enjoys organized chaos."

Manning stops fussing and turns to face them. "I couldn't believe it when I saw you at my door. I can't tell you how many times I've been on your website. 'The Science of Deduction'. My gosh, you're amazing." He blushes even harder. "I mean..." He looks at John. "And I read your blog, too. It's better than any detective novel anyone's every written."

Sherlock glances pointedly at the stacks of books. "You can speak with some authority."

Manning follows Sherlock's gaze self-consciously. "Yeah, well not all of them are novels. I've got a lot of technical manuals in there, too." He takes a deep breath. "I just can't believe you're here." He pauses as the obvious question dawns on him. "Why are you here?"

"You work on the databases at Scotland Yard?" Sherlock begins.

"Sure do. For the past four years." He crosses his arms, less awed now, but still staring openly at Sherlock.

Sherlock comes directly to the point. "How hard would it be for someone to break into the system?"

Manning uncrosses his arms. "What?"

"Specifically the database that is kept in the evidence room. I wondered if you had put any security in place since the system is intended for internal use only and is somewhat... unofficial."

The man hesitates, then shakes his head. "All of the databases are secure. It took a lot of overhauling, mind you. The guy who put together the one you're talking about didn't put any security into it at all, but it wasn't connected to the main system at the time."

"And it is now?" Sherlock wasn't sure until this moment that outside access was possible.

"Sure," Manning says. "I needed Internet access to support it remotely, just like the main. But the firewall is very secure. More so than most." That last part is said with obvious pride in his work.

"Did you make that change when you first began supporting it? Four years ago?"

"Yes. But you still haven't said why you think it's been hacked."

John picks up on where Sherlock is headed. "Before you added the remote connection, the only access was through the computer in the evidence room?"

"Yes. There aren't even that many people who know it exists." He crosses his arms again. "Now please tell me what this is all about."

"Would you be able to tell if anyone had accessed the records without authorization?"

"Yes, of course. The security software would text me a warning immediately. And there would be a record in the logs."

Sherlock suddenly realizes what's missing in the chaos of this flat. "Where is your computer set-up?" There's not even a clear surface to place a laptop.

Manning follows Sherlock's gaze, flushing all over again. "I do most of my work on site, not remotely. Remote access is for emergencies when I can't get to the site fast enough. In those cases, I use my laptop."

Sherlock smiles. "I apologize, Mr. Manning. I know you take a great deal of pride in your work, and it was not my intention to suggest that you do it badly." He catches John's brief puzzled look from the corner of his eye.

Daniel Manning studies Sherlock for a long moment. "Yeah, okay. I understand wanting to find out if the system is secure, but why not just call me and ask?"

Sherlock's smile remains. "Would you have believed it was me calling you?"

Manning's posture relaxes and the star struck smile comes back. "Probably not. You're right. It's really an honor to meet you, honestly. I'm a bit of a fan of your work." He nods to John. "Both of you have my dream job. Catching uncatchable criminals. Solving crimes when the police can't figure it out. If you ever need a hand with your website, I'd be happy to help. No charge."

Sherlock offers his hand, and Manning shakes it enthusiastically. "I wouldn't think of taking advantage of you, Mr. Manning. Your customary fees would apply."

Manning beams. "Any time." He shakes John's hand, then glances around and spots his phone on the cluttered work surface by the sink. "Could I have your mobile number? I'll take a look at the security logs, just to make sure. I could let you know what I find."

"It's on the website."

Manning nods. "Yeah, I knew that." He puts the phone back, looking a little sheepish.

"But I'll take your number, if you don't mind," Sherlock says, then keys the number Manning gives him into his own phone.

Outside, they walk up toward the main road in search of a cab.

"So what were you apologizing for, other than effect?" John asks, dubious smirk firmly in place.

"Aren't you the one who preaches the advantages of honey over vinegar?"

John snorts. "The last thing he needs is encouragement. I thought he was going to ask for your autograph."

Sherlock spots a cab halfway down the block and steps to the kerb, arm raised. As he flags it down, he gives John a narrow look. "You didn't think that seemed a little forced?"

John looks at him. "No, not at all. Why?"

The cab stops in front of them, and they get in. Sherlock directs the cabbie to Baker Street before he answers. "I think feigning surprise is an excellent way of disguising something else."

"Something else. Like what?"

Sherlock turns to look out the window. "Like not being surprised at all."

He unlocks the door to his flat and strides to the bank of computers to scan the messages on each screen. It's been a day full of surprises, none of them pleasant. He expects the trend to continue in his message queue.

Sherlock Holmes is on his trail, and it is only a matter of time before the genius detective realizes what he's found.

He's always known that one day he might be faced with this choice. Allow himself to be caught, or do whatever it takes to protect the Project. Allow deadly predators to remain free to kill again, or take one innocent life to save the countless potential victims of the men he's been eliminating. The ones the law can't touch. Victims like Jessica. If someone had had the courage to do what was necessary back then, she would still be alive. How can he condemn the men who let her killer go free, and not show courage to do better himself?

The deaths he's been responsible for up to now have been executions, not murders. But what he's considering now could be called nothing else.

End of Chapter 4