so the forensics came back on justin price, and the blood on his boots does match the victims at the crime scene. we got a second shooter. yeah, but there's another problem. the gun that david and colby found on price at the cyber cafe only matches two of the five kills that he's credited with at the high school. yeah. wait, he didn't have any others on him? no. and, like the first shooter, he was probably packing more than one gun, which means that gun is still out there. yeah. plus the rest of the uncle's arsenal. right. so now we have a bunch of guns and a bunch of really emotional kids who might have the potential of getting their hands on them. all right, so let's get every single kid in that dmg on surveillance, right? i mean, we got to find those guns. at 11:02:58, scott kang was at x-y coordinates 335/ 211, heading north. oh, evolution is a cruel mistress. human intellect grows unbounded, while our emotional maturity is sadly behind. larry? high school will always be high school, you know? the jocks versus the geeks, and the popular versus the ostracized. i remember. yeah, but, you know, time was when we solved our differences with fists, not automatic weaponry. times change. and it's not just guns. rfid chips and tracking systems. if this weren't the new millennium, i'd swear it's all very 1984. mmm. you know, megan feels the same way. speaking of, what was that smile she gave you all about? oh, it's her smile. ask her. wait a second. can someone clue me in here? well, the fact is, for some time now, though it's not my specific discipline, i have felt a certain chemistry with megan. which you've kept fairly well under wraps. precisely why my next overture will be overt. you're going to ask megan out, larry? yeah. but i don't know. given our disjointed universes, i'm... i'm fearful. what is it, charlie? this last grouping of data entries... it shows students running towards the shooter, and not away from him. but that obviously doesn't make sense at all. it could be an anomaly in the data. or an anomaly in the school. these school plans are old. walls could have been moved, obstructions introduced... if you're suggesting what i think you're suggesting-- field work-- god, i vowed never to return to high school. mrs. price, your son justin was associated with a group of boys at school known as the "dark matter guild." what can you tell me about them? just that they were friends who would hang out, play video games. and have you ever met any of them? i met paul elins a few times. i never met any of the other kids. i work in health care. it's long hours. i'm on the road three days a week. i wasn't able to keep tabs on justin the way i would have liked to. that sounds like you were concerned. i asked my brother john to spend some time with him. you know, i wanted him to have a male role model. he was in the service. i thought he could teach him. but, after john was killed, it affected justin. nothing that i said mattered. and, mrs. price, do you know where your brother john kept his collection of guns? i asked him to get rid of them. i assumed he had. we think there's more guns out there. i ran a credit check, and found a storage unit that was leased in your name. the fees were paid by money order. i didn't know anything about it. you think i'm an awful mother, don't you? i think you're a woman who's lost her son and feels responsible. my son murdered a teacher. he killed all those children. how do i live with that? the banality of evil is only banal to those who never see it. my senior year, a student showed up at school with a gun. he held two kids hostage. what happened? eventually, he let them go. then he climbed up to the roof and jumped. it's a different world than the one i grew up in. any structural discrepancies we had hoped to find, we're not finding them. now, given the rate at which my calculations show that the shooters moved... hey, you guys, you know what? i'll tell you what. you guys mind if i borrow your walkie-talkies? thank you. thanks. what... what are you thinking here, charles? you suggested i test my equations in the field. time me. okay, larry. time? uh... 58 seconds. charles, what is it? i need to talk to don. we searched that storage locker that justin price rented. found some unused ammo. but if he was storing guns there once, they're not there now. we did find this. take a look. it's a security schedule. yeah. it shows that the metal detectors were down at the southeast entrance of the school the morning of the shooting. all right, so they knew exactly where to enter. yeah. we found downloaded blueprints of the school, too. hey. what's this? it's a home-made "modded" video game we took off of justin price's laptop. he was playing with paul elins the night before the shooting. what do you think? like some kind of dress rehearsal? only they weren't the only ones playing. we have evidence other dmg kids were online as well. hey, guys, there's a problem with the rfid data i need to show you guys. all right. well, put it up. okay, i managed to map the movements of the students. now, these red dots-- these are students. and the black x's-- those are the shooters. now, during the first two minutes of the attack, the students behaved as one would expect. all right. well, then, what's the problem? eventually, a group of students actually started moving toward shooter number two. maybe there was a dead end over there or something. no. no. i walked those halls. there was no dead end, david. but check this out. these are the locations and the times of death of our murdered victims. now, according to the data, the time between the murder of victim number four and the murder of victim number seven was 33 seconds. however, i retraced the steps of shooter number two, and i found that where victim number four was murdered to where victims numbers five, six and seven were murdered, took twice that amount of time. so what does that mean? we know that shooter number one took out these three victims. and we know shooter number two took out these two. what about the other three victims? there's only one explanation for the aberration in the anomaly, and that is that you guys aren't just looking for a missing gun. guess what? you're looking for a third shooter. ( hammer cocking, gun firing ) with less chronic low back pain. imagine living your life with less chronic osteoarthritis pain. imagine you, with less pain. cymbalta can help. cymbalta is a non-narcotic treatment that's fda-approved to manage chronic musculoskeletal pain. one pill a day, every day, can help reduce this pain. tell your doctor right away if your mood worsens, you have unusual changes in mood or behavior or thoughts of suicide. antidepressants can increase these in children, teens, and young adults. cymbalta is not approved for children under 18. people taking maois or thioridazine or with uncontrolled glaucoma should not take cymbalta. taking it with nsaid pain relievers, aspirin, or blood thinners may increase bleeding risk. severe liver problems, some fatal, were reported. signs include abdominal pain and yellowing of the skin or eyes. talk with your doctor about your medicines, including those for migraine, or if you have high fever, confusion and stiff muscles, to address a possible life-threatening condition. tell your doctor about alcohol use, liver disease, and before you reduce or stop taking cymbalta. dizziness or fainting may occur upon standing. side effects include nausea, dry mouth, and constipation. [ male announcer ] ask your doctor about cymbalta. imagine you, with less pain. cymbalta can help. go to cymbalta.com to learn about a free trial offer. cymbalta can help. hershey's air delight. experience light and airy, melty bubbles. made from pure, delicious hershey's milk chocolate. hershey's air delight. why you... nobody's taken a shine to me in a long time. phooey. i don't need anybody...but you! ♪ i believe in miracles [ male announcer ] swiffer attracts dirt. used mops can push muddy water around. swiffer wetjet's new, upgraded solution helps prevent streaks and residue to reveal more shine than a mop or your money back. you're a fresh swiffersnapper! agent reeves, my secretary says that you think there was a third shooter. i'm afraid that's what it looks like. first these shootings, then justin price gunned down. now you say another one of my kids is involved? where does this end? i think as soon as we find this third gunman. i wanted to reopen school, get the kids back to some kind of normal routine. i can see now that's not possible. mr. northrup, right now we need your cooperation. we need the files of everyone associated with the dmg. that might be a problem. what do you mean? why? well, the parents of these children feel their kids are being unfairly singled out. they've hired lawyers and they make it clear that they won't consent. so you're saying we need a court order? i'm afraid that's what it's going to take. there may be another way. how? construct the information from public records. military personnel have the same access as colleges. transcripts, activities, club memberships. justin price had a criminal record. maybe one of the members of the dmg does, too. anything in the public record we can use the patriot act to get at. eight dead, 12 wounded. i'd call that an act of domestic terrorism. megan: more files. sorry, team. oh, it's okay. charlie promised to take a look at the data for my solar physics presentation. thank you. and you still think you can do this in one day? yeah, using my support vector classifier, yeah. sure. see, the algorithm's going to go through it all, okay? grades, activities, disciplinary actions-- to evaluate traits ascribed to the fbi's school shooter profile. still seems like a really tall order. you know, michelangelo always said that his sculptures already existed. it was merely up to him to release them from their prison. well, what he means is that this process is a lot like that of a sculptor. preserving only what's relevant to the image he seeks, a sculptor chips away at a block. well, in this case, the algorithm tells the computer which details from the public records to keep and which to "chip away at"-- which to discard as irrelevant-- until slowly an image appears from this massive block of data... which, you know, if we're lucky, correlates with an already existing image: a profile of our random school shooter. i know a lot of women who'd like to get ahold of your algorithm and run it against the personals to find the perfect man. oh, hey, you know you said we were supposed to do something earlier, remember? you said it. what? we're supposed to do it. let's go. right. see ya. right. bye. what was that about? merely a very crude attempt at lending privacy. at the risk of sounding embarrassingly misguided, would you care to join me for dinner? or a show, perhaps? or maybe even some terpsichorean pleasure? i don't know what the third one means, but dinner sounds nice. okay. ( chuckles ) on one condition, though: you have to take me for a ride in the car. delighted. call me. i will. i will call you. ( chuckles ) charlie said he's halfway through his analysis. so far, he's got no hits. we're stuck without those student files, i can tell you that. what about the court orders? the kids' lawyers are hemming and hawing, so it may take the judge another day. i'm hoping this may help. i found on the school's isp in the deleted files an e-mail sent out the day before the attack cc'ing all the members of the dmg telling them to be careful at school the next morning. guess who sent it? what, gregory dietrich? there you go. yeah. so i'm gonna give it to the judge and i'm hoping if we push, we might be able to get a warrant for his file in the next couple of hours. all right. do it. pick up the kid, but let's be careful now, all right? still revisiting high school, charles? just mapping our shooters' third route. you got a date, huh? you don't seem too excited. mine is an inner frenzy. like some highly agitated molecular brew. i can't even settle on a restaurant. well, you know, italian's always romantic. the kinetics of angel hair and red sauce, it's a bit too much of a challenge, i'm afraid. plus, i think i prefer not to wear a bib. i think you need to loosen up, you know? free your molecules, and your ass will follow. oh, yeah, well, sound advice. amita: i just ran gregory dietrich's student file through analysis. he's the leader of the dmg. he scored off the charts on the fbi's school shooter profile. our algorithm came through, my man. larry-- still debating the complexities of capellini. no, i'm just considering the complexities of shooter three's route. if your main goal was simply to shoot other students, why such a convoluted path? i don't know. insanity maybe? oh, no. even a crazy person can get from point "a" to point "b." megan: two months ago, gregory dietrich made an online purchase of an "evil twin" kit. what is that? it's a hacking device to tap into wifi networks and steal sensitive data. so what? so they can get blueprints and security schedules, stuff like that? exactly like that. our guys detected a wifi breach at the high school security data base a week after dietrich bought the device. traced it to him? yeah, the kid's not so smart, after all. further proof of that. surveillance just saw him running into his house like a man on a mission. ah, the lawyer must have tipped him off. he's making his move. colby: i can't get my head around this whole high school shooting thing, you know. i mean, i came from a small town. there's 200 kids in my high school, not 2,100. everybody knew everybody. if some punk was running around with a pile of guns and bad intentions, we'd know about it. i don't get it either, man. where i grew up, this kind of stuff didn't happen. don't get me wrong. kids got shot, but it was over something, you know? pair of sneakers, insult, drugs. it was definitely stupid, but looking at those kids shot in their own school... wouldn't have thought about it at the time, but... maybe we were luckier than we thought growing up where we did. yeah. there he is. five bucks says he runs. yeah? ten bucks says i catch him. i got the bag! ( siren blips ) ( tires squeal ) you should spend a little more time in p.e., kid. going hunting, gregory? i got nothing to say! yeah. that one's new. stand up. let's go. ( gunshots ) my client already told you he had nothing to do with the attack on the school. your client was in possession of a semiautomatic weapon. a gun that was part of a collection that was owned by justin price's uncle. which doesn't prove a thing ,unless that gun was used in the attack. why'd you have it? you don't have to answer that. no, no, it's okay. i want to answer him. justin gave me the gun. we'd go off into the woods. we'd fire off a couple rounds at cans and stuff. and while you were out there, no one ever mentioned going and shooting up the school? that i won't let him answer. you bought a device to hack into the school's database to steal blueprints. we have your name right here. we traced it to you. it's your name, isn't it? those blueprints were for my game. for authenticity. for authenticity? wake up. these are kids you went to school with. they were shot in cold blood. authenticity. it wasn't me! but you hated them, didn't you? look, why don't you guys try living with it every day? the way they look at you like, like you're not even there. so you took your revenge. it was paul and justin. but you wish it was you, don't you? i think we're done here. megan: his lawyer's right, you know? the gun we found on him isn't a match for our missing weapon. colby: you're not going to like this much, either. his e-mail story holds up. that warning that was sent out to the other dmg members? it was sent from his account, but it originated from the school library. so he sent it from the school. not unless he was in two places at once. his school i.d. badge says he cut out early that day. his atm card and a security cam photo says he was making a withdrawal the same time the e-mail was sent. he created the game, he's the leader. all this goes down and he's got nothing to do with it? i don't buy that. ( knocking ) charlie, your advice-- "free your molecules"? i made a reservation for megan and i at an ethiopian restaurant. ethiopian, on fairfax. thinking outside the box. wish me well. hey, you know, um, you were right. shooter number three's route doesn't conform to any predictable pursuit-evasion result. i'm thinking that i must be missing a variable. up until now-- i got to be honest-- i think we've been looking at this school shooting the wrong way. let's take a look at the route taken by our first two shooters. their movement is methodical. they are pursuing students in a logical progression. now let's take a look at our third shooter. appears here and for the next minute makes his way through the school killing victims until vanishing here. most likely changed clothes. shooter number three's route is circuitous. it's inefficient. yeah, but it's a random shooting spree. doesn't it make sense that he'd choose a random path? intuitively, yes, but, well, mathematically, no. mathematicians apply a path minimization to analyze this kind of predator-prey dynamic. what exactly is that? the snake pursues the mouse. mouse runs, the snake is relentless and tracks every step. and when it runs into obstacles, it finds the quickest, most economical way around them. now using path minimization, we can predict the snake's path because the snake only has one thing on its mind-- finding the most efficient point a to point b between it and its dinner. so shooter number three is just a lousy snake, or what? shooter number three's route was definitely not determined by path minimization. so... what then? maybe this. now we know that the school uses rfid chip technology to take attendance; tells teachers when students are in class and when they're absent. keeps track of students using a pda. right. names and locations of the students show up on the screen. the dmg kids, we know they have the capability to break into the school security system. yeah, so why couldn't they hack into the rfid? they definitely weren't taking attendance. charlie's right. can you bring up the model for shooter number three? look at the behavior in the model. david: he's letting the students go right by him without even taking a shot. because he's targeting specific students-- the quarterback, the skateboarder and the swim team captain. and the system would tell him exactly where they are. larry: oh, that... no, that's sufficient. ( african music playing ) thank you. so the last time i had ethiopian food i was at a conference on bondi accretion in addis ababa. ( laughs ) what? oh, am i being tedious? no, no, tedious would be a week at quantico studying note-taking skills at a crime scene. oh, speaking of which, i heard you and charlie went down to the school. yeah. it was horrific. i just kept thinking all the while, you know, if i could only corral a wormhole and go back in time, just talk to these young men before they did it. and what would you say to them? i would say high school is ephemeral. and i don't know if the meek inherit the earth, but bill gates and the google guys... you know, they did all right. you seem to have done well. no. well, now, but in high school? oh, i don't think you and i would've been at the same table. in fact, i wasn't permitted a table. i was kind of a mess in high school. yeah? that surprises me. it was a surprise to most people, particularly my parents who could, you know, barely show their face at the country club for a while. oh, no, country club. you're one of those. social register, too. you're full of surprises, you know that. so this fbi thing, why did you become a g man? well, it's a little more complicated, but i have three older sisters, and i was my father's last chance at having a son. i could play every ball game known to man. as i got older, it just got harder to switch gears. in fairness, i should say that the fbi has given me the greatest sense of equilibrium i've ever felt... on most days. you do seem a little distracted tonight. it's just the case. you know, charlie's math shows that our main suspect fits the shooter profile for a school shooting. but his math also shows us that our shooter number three wasn't on a killing rampage. you know, i'm failing to see the inconsistency. the first two shooters fit the profile of a school shooter. they show unbridled rage. this third shooter... was calculated. it was a planned attack. it's indicative of a whole other motive. you know, in cosmology, when faced with logical inconsistencies, i like to fall back on an old chestnut: if you don't like the answer, ask a different question. don: 6:00 a.m. i get a call from charlie saying we got some new angle on the case. it was something that larry said to me over dinner last night. wait, wait, you and larry had dinner last night? oh, god. moving on. he just got me thinking. you and i both have our doubts that dietrich is the third shooter. right. so what if we need to look at this in reverse? what if we need to study the victimology? shooter number three picked all of his targets for a specific reason. there has to be a reason why. oh, i see. so, what, just have charlie do what he was doing with the suspects, but do it with the victims? yeah. if we can find the common denominator it might take us back to the killer. all right, that's good. where'd you have dinner? so i ran a cluster analysis on the student files of our three victims-- rob holt, skateboard dude; thomas caballo, quarterback; and louis ives, swim team captain. the two jocks share numerous commonalities-- they're both seniors, both captains of their squad. what about skateboard dude? his only commonality is that his name appeared in an investigation of steroid abuse by student athletes. he was a suspected supplier. some of the students mentioned that. the school investigated, but nothing came of it. any other correlations? all three names appeared in a police report of a keg party that got so rowdy the neighbors complained. however, there were a dozen students on that report. none of them were victims, none of them had any apparent relationship to the victims. yeah, but still, maybe something happened at the party. yeah, something enough to motivate a killer. you got a list of kids at the party? can you put it up? yeah. we just need to find the connection between these names and one of the dmg kids. karen camden. wait a minute, she was on the police report? she has a connection to all the dmg kids. yeah, she wrote a story about them for the school paper. she knows them really well. she knows they were having violent fantasies. yeah, but why would she want to take part in this attack? i don't know, but it might explain why they spared her, not just because she gave them props in the school newspaper. absolutely. maybe she's in on it. megan: karen camden purchased a wifi pda three weeks ago. okay, so that would allow her to track anyone in school, right? her credit card showed a bunch of charges to a motel in the valley. the manager id'd her and justin price. oh, a pretty girl could get a teenage boy to do a lot of things. especially if he's not used to the attention. and if he has the inclination. look at pamela smart, she got one to kill her husband for her. so what, she seduces price, uses him and blows him off? she could've even gotten him to shoot paul elins, his own friend. she could've made up the whole murder-suicide pact. probably knew he was fantasizing about the shootings and then just pushed him over the edge-- and becomes the third shooter. why? what's the motive? well, best guess, we look at the victims. the answer's probably going to lay there. school steroid scandal. article was written by karen camden. i thought that investigation went nowhere. no prosecutions, but some of the team captains lost their college scholarships. yeah? just to get even, huh? karen's not a violent person. she'd never do anything like this. yeah, but something happened at that party, didn't it? something that changed your daughter. mrs. camden, we have eight people dead and 12 more in the hospital. if you know the reason for this, we need you to speak. they raped me. becky was the one who set it up. she invited me to that party. helped rob holt, mr. skateboard cool, slip something into my drink. then jake porter raped me and the others watched and took pictures. oh, god, karen. god, honey. i wrote that story about the steroids. they blamed me for messing up their scholarships. why didn't you press charges? they were the stars of the school. it would be my word against theirs. they had to pay. karen, eight people are dead that you went to school with every day. i'm going to need you to put your hands behind your back. ( handcuffs click ) i'm sorry, mom. i'm sorry. i'm sorry. david: jake porter. yeah? take your headgear off, tough guy. we want to talk to you. what's this about? you're under arrest for the rape of karen camden. what are you talking about? megan: we spoke to karen. she gave us a statement about what happened at the party. you're talking about the same girl who shot up the school with her psycho-geek pals, right? everybody's talking about how she's the one who engineered the whole thing. you're telling me you believe karen camden? the girl's a whack job. it'll be my word against hers. megan: yeah, would've been. except for rob holt's cell phone. your moron friend took a picture of you with his phone. david: let's go. turn around. i'm not going anywhere with you guys. yeah, you are. you're coming with us. get off me. what is it with guys and dirty pictures? stand up. charlie: where's big papa? the caterer. ah, getting serious. i just think he doesn't want to have to cook, you know? charlie: you never get enough? don: look, what do you want from me? i like seeing how they spin it, you know? you think anybody really knows how any of this stuff happens? definitely not. i know that when i was in high school, i was so... uh, angst-ridden. yeah. but i mean, you didn't shoot anybody. no, but there were days when i wanted to do, you know, real... real damage to... to you. to me? hey, buddy, take your best shot. come on. wait, i'll help you out, i'll get on my knees. come on. i'm not a kid anymore. all right. tough guy, let's go. maybe we should step outside. all right. how about now? how about now? let's go. come on. you ain't got nothing. all right, all right. how about we just get pizza? no, i don't want to go out, man, i just got home. there's a lovely pot roast in the fridge. it's a week old. come on. how do you know that? of course. you eat here more than i do. i'll pay, how's that? captioning sponsored by cbs and paramount network television have asked yours truly to teach you about treating frequent heartburn. 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