tonight, tonight, "20/20" -- >> how to get away with murder. >> move over, viola, there's a new teacher in town. >> if you want to learn how to clean up a crime scene -- >> did he teach students how to commit the perfect crime? a young woman obsessed with

>> tonight, "20/20" looking for all the clues to find her, or her killer. the three men, interrogated. the ex-boyfriend, the guy who wanted to be her boyfriend. and his roommate, what did he see in the dark of the night? but it's her grieving brother who >> it doesn't make sense why she's gone. i don't get it. >> using a hidden iphone to catch the killer. >> you killed my [ bleep ] sister. >> tonight, could it have been a script from a tv show? >> we bury the evidence. >> those are things he could have learned in my class. >> how to get away with murder.

>> reporter: young and pretty. lost and nowhere to be found. lea porter, a 19-year-old colorado waif of a woman who simply vanished in june of 2014. >> she was small, but she was feisty. >> reporter: police launch a massive search in the denver suburbs. >> they are still looking for lea porter. >> friends and family are desperately searching for lea porter. >> reporter: and now more than two years later, lea, still not fod. her mother rene jackson follows her own leads. tramping through the winding, dusty trails of central colorado with search dogs, ignoring warnings, keep out, private road. it may be your last earthly move. >> okay, go find! good boy. >> reporter: why come now, obviously the police aren't searching for her? >> because, my mama heart can't just -- i can't accept the fact that i don't know where my daughter is.

wendy kessinger of k9 forensics and her dogs are searching here on deer mountain. it looks almost a little needle in a haystack. in cotopaxi, colorado, population 47. its claim to fame, whitewater rafting through one of colorado's deepest canyons, royal gorge. >> cotopaxi is really in the middle of nowhere. it's three hours from denver. it's a mountain town. people live far away from each other. there is barely a stoplight. and thma general store which is also a gas station, and it's also the only restaurant in town. >> reporter: it's also where the vivacious teenager grew up. a future as bright as her personality. >> she was an amazing young woman. kind of a joker. she loved her brother like crazy. she was very social. she had lots of friends. >> reporter: among those friends, high school bf malorie nixon.

you know, she could've met someone five seconds ago and she'd alread she'd already feel like their best friend. >> reporter: at cotopaxi high, lea is an average student. more interested in the social scene than academics, hanging with the art crowd, deep into electronic music and concerts in faraway denver. a small-town girl, anxious to record her every move on her camera phone. >> she was kind of a selfie hound, which i used to make fun of her, like, get that p your face! but i'm glad she took as many as she did for sure. >> reporter: because now, it's all mom has -- memories. and as lea moved away from the slow pace of cotopaxi, the memories begin to turn dark. a good girl, alone. now a two-hour drive from family, quickly slipping into a world full of temptation and danger. secretly dropping out of class, here at trinidad state college, and then moving in with an older man.

i don't understand what made her go to this -- to this person who was much older, and, you know, was kind of bad news, so. >> reporter: he's 38, she is not out of her teens. jessie mine, a tattoo artist who malorie nixon says has a taste for tender young women and hard drugs. she wasn't involved in drugs at all before she met him? >> not before she met him, no. >> reporter: and then, how bad did it get? >> it t we were going to a concert together and as we were driving up to denver, she said, "i did heroin for the first time, and i'm hooked on it." >> reporter: what did that say to you? >> it broke my heart. it really did. >> reporter: while all this is happening, lea's heart is broken too, by another man. a man she is closer to than any boyfriend. her older brother maxx. >> she was basically like my best friend.

listened to the same music. did the same things. fought like brother and sister all the time. and we were really close. we were able to go to each other and talk to each other about everything. >> reporter: but when lea needed her brother most, just as she's meeting the older man, maxx, not expecting the downward spiral to come, moves to california to open his own business. >> she got really depressed and then she met jesse. >> he's a 38-year-old guy. >> reporter: so she was attracted to this older man? >> yes. but he lied about his age at first. and then later after they clicked, then told her. >> reporter: was there a certain vulnerability about your sister that perhaps allowed this to happen? >> she lets people in really easily. so if you show any affection or care she'll most likely open her arms up to you. >> reporter: lea porter knew her life had taken a turn for the worse. desperately looking for a course correction. her friend malorie says in the

she was struggling to kick a heroin habit, attending narcotics anonymous. >> she said she wants help but she doesn't know what to do. she doesn't know who to go to 'cause she didn't want to leave jesse. >> reporter: was she getting out of it, do you think? >> oh, she definitely was. the day before she went missing, i saw her down in pueblo and she had been off of it for three days. >> reporter: the trouble in lea's life is about to get worse. jesse breaks up with her, packs his truck and moves ea live. she packs her car and heads north to denver with no real plans. so lea starts looking for help on social media. telling a facebook friend, "i'm about to be homeless." and then, as her brother finds out, she just drops off the grid. >> i knew there was something wrong right away because i couldn't get ahold of her. it was just days of calling back and calling, calling, calling, calling. called my mom. told her there's something wrong.

police, who immediately turn to boyfriend jesse. his trip to the east coast cut short by a summons to the interrogation room. >> can you tell me what your relationship is with lea? >> reporter: for 90 minutes police hammer jesse, and he admits to some rough times. >> it was like the biggest fight we ever had. >> were you guys arguing? >> no, not hitting each other. just screaming at each other. we would fight about cheating on each other. >> reporter: coming up, is this one of other men in lea's life? this is the last time she was seen, having lunch, but who's that picking up the tab? and what did he learn in a criminology course like this one? >> this is criminal law 100 or as i prefer to call it, "how to get away with murder." >> hello. >> hello. i'm elizabeth vargas. >> and i'm david muir.

question, would a student use this in a real class to try to get away with murder? >> let us know on facebook and twitter. coming up, whose name keeps popping up on the phone bill? ? he's gotta play it cool to seal the deal. ? ? better find a way to smooth things over. ? ? if only harry used some bounce, to dry.? ? yeah. ?

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of how to get away with murder. >> reporter: the matching piercings, body art and heroin, not enough to keep teenager lea porter's passionate six-month relationship with jesse mine, nearly twice her age, alive. >> and i fell in love with her, man, fell for her hard. >> reporter: police have some tough questions for jesse, who tells them in the interrogation room that despite the break-up he still had plans to marry lea in the future. >> t if she got help, if she got clean, that i would love to come back and marry her. >> reporter: jesse tells the cops he last saw lea when they parted ways at this motel parking lot, just outside denver. he describes a dark scene, saying lea was distraught and maybe thinking of taking her own life. >> she begged me not to leave. she talked about killing herself. she didn't have anything left to live for.

maryland to get off drugs, she was off to denver to crash at a friend's house. but right after they separate, jesse says something weird and completely out-of-character happens. lea, the girl who is always on her phone, suddenly stops texting him. >> so, that first night i was worried, but not too super worried, thinking maybe she's just mad at me, and then the following day when maxx called me and said, "yo, dude, where's my sister?" that's i when i was like, [ bleep ]. something, something bad has happened. >> reporter: bad, because jesse says lea always takes maxx's calls. no matter what. >> she would stop during sex to answer a phone call from her brother. >> is that right? >> it was like that, it kind of caused fights a few times. >> so they would communicate how often? >> every day. >> reporter: jesse appears cooperative in the interrogation, but admits lea's

>> maxx had convinced them all that i was not to be trusted. i was the devil. >> reporter: back home in cotopaxi, her mother rene is running down another lead. it's a mom on a mission, since rene pays lea's phone bill, she examines her daughter's call log. and begins phoning every number on the list. >> this one number kept popping up over and over, and it was christopher waide. and i had never heard that name before. >> reporter: christopher waide, a tall and slender 23-year-old. he to high school with lea, where he was a top student but was often bullied and teased. he joined the military in an effort to toughen up. now, waide is taking jujitsu for self defense. but talking to christopher waide only brings heartbreak for rene when she learns he's been lea's self-appointed accountability partner. a kind of sponsor to help her stay off drugs. >> that was the first time i

drugs, was from christopher. >> reporter: it seems lea might finally have found a a safe place. christopher tells rene lea was with him at his apartment the night she disappeared, but that she left abruptly, without explanation. >> he told me that she had gotten a notification on her phone late that night and left. >> reporter: christopher waide says he hasn't seen her since. but this is another man the cops need to talk to, paying him an immediate visit. westminster police detective matt calhoun is in charge of the ca what does he tell you? >> they had been conversing back and forth. he had offered to let her stay at his apartment for a couple days to try and get her feet under her. just concerned that lea was suicidal. >> reporter: did he seem like he was anxious to help? >> yeah. he really was. he really wanted to help find lea. and he's really concerned about her. and he wanted to do anything he can to help us. >> reporter: just like lea's boyfriend jesse, chris waide is extremely helpful, full of detail and concern. after interviewing these guys, police aren't yet convinced lea

it's possible she just is a runaway. >> we don't know what happened up to this point. and we can't prove that even a crime happened at that point. >> reporter: waide even joins the search, pleading for her safe return online and on the local news. >> i tried texting her, i've tried calling her, left her some messages on facebook and haven't heard anything back from her. >> reporter: lea's family is busy too, plastering missing posters all over the centennial state. now desperate, they turn to the public to plead for lea's return. >> i don't want anyone to hurt her. i just want her home safe. she's just a tiny little thing. >> if she is out there somewhere please come home to us. we need her. everybody needs her. >> reporter: lea's brother maxx is back from california, and starting to stew. feeling like the authorities aren't keeping him in the loop.

they were really vague. >> reporter: no sign of lea, and no leads until lo and behold, lea is spotted at a boston market, in line for some chicken. she's in shorts and flip-flops, seemingly unharmed or distressed but with a mystery man buying her lunch. >> reporter: coming up, yet another man is under suspicion, a roommate in that apartment where lea was the night she disappeared. that makes three. and the impatient brother maxx is laying a trap for one of them. when did you guys were going to have to do some of this on your own as a family? >> we just did. >> reporter: a confrontation with a killer. >> you tell me right now what happened to my sister. >> reporter: next. ?i live in a nameless town? ?in a black out? ?midnight where we used to dance?

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right no right now, westminster police hoping you can help find this missing 19-year-old. >> a teenager missing nearly a week. >> she hasn't been seen for more than a week. >> her family hasn't heard from lea porter since thursday. >> porter. last known whereabouts, this apartment complex. rented by an old high school classmate and facebook friend, former military helicopter mechanic 23-year-old christopher waide. >> porter and waide went to the same high school. porter went to visit waide at his westminster apartment and then was never seen again. >> reporter: he seems touched about her disappearance on tv. >> i don't really have very many

losing one is a heavy blow for me. >> reporter: with christopher's permission, police search his tiny two-bedroom apartment where he lives with another army vet. but it's less bachelor pad and more like female repellent. in the living room, video games and soda bottles scattered across the carpet. >> it's just filthy. there's two-liter jugs of chew spit. clothes all over the floor and dishes all over the floor. >> reporter: the kitchen, dried-up food, half-eaten takeout and not a sponge or soap in sight. >> it was hard to be in that apartment. it smelled pretty bad. >> reporter: but worst of all, christopher's bedroom. a chaos of clutter. clothes, coupons, computers, and camouflage cover the floor. >> it just i >> it just in disarray. twin mattress on the floor with no sheets, and then no pillowcase. >> reporter: but amid all the disorder, a key discovery. glistening through the messy melange, a blade. now the cops are more than curious and christopher has some explaining to do. >> you can see the little bleach

about a week and half earlier, and he explained that's why he bleached his knife. so that's when we actually asked him to come in for a formal interview at the police department. >> reporter: here at headquarters, detective calhoon calls for backup. bringing in the grizzled veteran homicide investigator mike lynch to get first crack at the would-be cop, with a stinky apartment and a story that's beginning to smell just as bad. we move to interrogation room number two. this is the interrogation room where you got to speak to >> we always put the subject that we're talking to on this side of the table. and then there's two cameras, one there and one there. >> we're not forcing you to talk to us. you are going to be free to leave when we're done here. >> all right. >> he was a person of interest and possibly being considered only because he was the last person that had been with her. >> reporter: christopher describes his background in detail. he was raised in a deeply religious household. but he has a pagan obsession, proudly showing police the tarot cards he carries around, even

>> the first thing that popped out to me was the combination of the high priestess and the ace of wands. usually the two of those together would indicate either a pregnancy -- >> so you actually asked her about being pregnant? >> she told me that she had missed her period. >> reporter: the conversation then turns to what exactly was the relationship between the two of them. christopher insists it was totally platonic. he >> i liked her and don't get me wrong, she is a beautiful young woman but in no way did i make any advances on her whatsoever. >> reporter: even in the interrogation room, waide is still helpful. he volunteers information, even points to this facebook message she sent him. >> she had just gotten out of a bad relationship and she wasn't looking for a relationship or anything like that and i told her straight up that's fine by

advances, not me. >> reporter: and sure enough, according to christopher, at his apartment that night, the pretty 19-year-old went after the 23-year-old geek. >> we were just getting ready to get back into the video game then she leaned in and kissed me and then i kissed back. >> reporter: what did you think of that? >> a little unusual and a little odd. because mr. waide was a little bit of an unusual person himself. and it kind of caught us by surprise that she would want to have sex with him. >> reporter: unsure of what to make of the story, detective lynch begins to question christopher about something conspicuously absent from his apartment, the sheets on his bed. >> you didn't get rid of the sheets? >> no. >> intentionally get rid of the sheets, because maybe they had her blood on them? >> no, sir. >> it seems inconsistent just based on the condition of your apartment that you would be all of a sudden in the middle of a sexual experience, taking your sheets and take them off the bed. >> it was afterwards. >> but even afterwards it seems kind of bizarre. >> the worst thing you could do is lie to us.

>> reporter: christopher cracks like three-minute egg. backpedaling under pressure. he tells his interrogators when lea's mom called him that first night, saying she is missing, he panicked and trashed the sheets that had both their dna on them. but detective lynch is beginning to think there was more than sex going on in that bedroom. >> we started turning the heat up. and i asked him, "where's the body at?" i says, "is that body out there with the cell phone? did you kill lea pte >> it sounds to me like yes, and i maintain my innocence, but i would like a lawyer. >> our interview has to cease. and even tho and even though at that point in time, i'm convinced he killed her, we have to let him walk out of here.

free. but the police are closing in. turns out, christopher has a roommate. jesse williams. he is in he is in the hot seat for three hours. >> did you ever hear >> reporter: >> reporter: but he did see something curious. the roommate is sleeping on the living room couch, such as it is. at around 3:00 in the morning he watches as christopher takes something outside. >> i'm just transferring stuff that was in my old car to the new car. that's all he said. he went back to his room and i assumed he went to sleep.

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i mainta i maintain my innocence, but i would like a lawyer. >> reporter: >> reporter: 23-year-old christopher waide with his button-down shirt and goatee looks like a geeky college student, not the prime suspect in the disappearance of a teenager. >> we have chris under 24-hour surveillance. >> reporter: the detectives conclude are witnesses and not suspects. they let them go. and they get search warrant for christopher's apartment. >> our criminalist was able to do examinations for blood on, like, the bathroom. she sprayed the sinks and then the shower. and we were actually able to actually see a t-shirt that had a bloodstain on the upper sleeve. >> reporter: and then police hit paydirt. when they fi when they find, buried in the

thank heaven for 7-eleven. stocked as they all are, with slim jims, slurpees and security cameras. >> you'll just see chris waide coming from his apartment to buy the bleach and gloves. it looks like it's about 11:54 in the morning. >> reporter: watch as inside the store, he's no housekeeper but grabs the bleach. then after speaking with the clerk, rubber gloves before heading back to his mess of an apartment. the evidence is mounting. police match christopher's picture with the man in the boston market video. and they see christopher meet with someone new. >> he was still under surveillance. so we had detectives watching him and watching this whole thing go down. >> reporter: it's lea's brother maxx, unable to wait for police to go through the legal process. he is setting a trap of his own. luring christopher to this idyllic setting under a gazebo of all things with friendly text message text messages, like these.

anything but other people do. hope you are holding up with work and all, friend. i'll let people know to stop harassing you. >> reporter: and were you acting sympathetic at that point? >> yeah. totally. like i totally just told him what he wanted to hear. >> reporter: but it's all a ruse to bait christopher into talking. maxx brings along a friend and christopher brings his obsession, those tarot cards. he says he wants to do a reading to help find lea. maxx and his buddy eric fey show me the gazeb me the gazebo where they sat and talked. where is he sitting and where are you guys sitting? >> he's sitting on the corner right there. >> reporter: as christopher begins his tarot reading, max is getting impatient while chris rambles on about the cards. >> i'm seeing no physical harm or intention towards lea. >> reporter: and then in a genius move, maxx secretly records the conversation on his phone.

know. chris, look at me, right in my eyes. dude, where is she? >> i do not know. >> and then it went back and forth, like, ten, 20 times. >> you know what happened. >> you need to tell us right now, dude. i need my sister back, dude. i'm going to kill myself without my sister. chris, where is she? and eventually he cracked. >> look, you >> look, you have every right to be angry with >> >> you know if she's alive or dead? >> i do. >> reporter: christopher for the first time admits, right here far from the windowless interrogation room, under the lattice of a gazebo, in front of lea's brother, that he killed the teenager in trouble. claiming he did it in defense, self-defense. >> they went out to eat. she came back. they had sex. then she wanted drugs.

to stab him for drug money. >> reporter: here are christopher's own words. >> i turned, grabbed her, then stepped forward and twisted her around so that her body was in between me and the knife. and then i placed my hand at her throat. i didn't start squeezing until after she kept going. i told her - i told her -- >> how long did you squeeze her throat? until what happened? >> i thought that her muscles would relax when she went gradually move the knife away and let her go and let her regain consciousness. but that didn't happen. >> reporter: what are you thinking as this is going on? >> i flipped out. she wouldn't try to stab you, dude. she would never try to do that. you [ bleep ] lying sack of [ bleep ]. >> i know you won't believe me, but i will be turning myself in to the police. i will tell them -- >> no, you're going to jail right now.

where do you think you're going, man? >> reporter: christopher is not going far, unless he has a paddle. the gazebo is surrounded by water. he wants to leave and turn himself in to the cops the next day. maxx, just hearing a horrific firsthand account of his sister's murder, would have none of that. >> you think i'm just going to let you walk away and drive away? you killed my [ bleep ] sister. you [ bleep ] piece of [ bleep ]. >> reporter: that last sound you heard, that was maxx pouncing on brotherly love in the form of a fistful of personal punishment. >> i made sure that maxx got at least one good shot in on his face before i grabbed him and pulled him off. i wanted to jump over this bench and go at him myself, definitely. but i wanted him to rot more than that. >> reporter: you wanted him in prison. >> yeah, i wanted him to suffer in there. >> an amazing scenario that i'd never seen in 25 years of being a prosecutor. where a family member confronts

beginning. when maxx and eric call 911, they make him repeat the story on tape for a second time. the killer doing the talking. this is something you don't hear every day. >> 911? >> yes, i'd like to confess to a murder. >> okay, what happened? >> the case is for the disappearance of lea porter. >> reporter: but surprise, there is no need to summon the authorities. they been watching the detective matt calhoun is back at headquarters. >> and we hear from the surveillance units that maxx had just punched chris in the face. >> reporter: as the cops come out of the bushes, maxx is still making calls, this time to his mother. >> he was hysterical. and he told me that lea was dead. and that christopher admitted to killing her. i actually almost wrecked on the

911 call, a mother in hysterics. >> westminster 911. where's your emergency? >> oh, my god! >> ma'am? can you take a deep breath? what's your name? >> my child, my baby! my little baby! christopher waide! christopher waide! just admitted he killed her! >> reporter: did you think at all how amazing it was that your son and other friends were able to get him to say he did it? >> reporter: coming up, it's still a case without a corpse. >> step three, we bury the evidence. >> reporter: did this real life professor teach chris waide chris waide just that? >> his efforts to clean and purge the crime scene, those are things he could have learned right there in my class. >> reporter: how waide may still

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doubt. doubt. that's how you get away with murder. >> reporter: every week viola davis teaches the secrets of crime on "how to get away with murder." while in suburban denver, this real professor hits the chalkboard, teaching criminology to would-be police. >> we teach everything from interview interrogation, report writing, crime scene management, forensics. you name it. >> reporter: how does that help if someone doesn't want to do good but they want to do bad? >> if you want to learn how to clean up a crime scene, some of making sure that all the evidence is acquired, these are things they're learning. >> reporter: and guess who was in the front row, acing the class. christopher waide. >> he had some amazing analytical skills and was sharp as a tack. >> reporter: book smart, but oddly unable to connect. especially, wells says, with half the population. >> he was challenged when it came to even speaking and finishing a sentence with a

>> reporter: >> reporter: still, wells said he was a gifted but awkward student. top of the criminal justice class, honor roll at little everest college, dreaming of solving tough cases, like the one he is headlining now. back in the interrogation room, a quick frisk and a jab from the real cops about waide's lifelong dream to be on the other side of the law. >> i didn't miss anything, did i? you'd tell me, right? >> no, you didn't miss anything. >> reporter: >> reporter: sitting with his lawyer and the cops he wanted to be like, waide tells them his story of a struggle, a knife, and lea's death. >> i was the only witness as well as the person that not murdered her, but was responsible for her death. >> reporter: but what he did afterwards convinces police this was no accident. waide didn't call 911. instead he took steps to hide

>> i re-clothed her, and i placed her on the bed, and then i took a duf i took a duffel bag from my closet. >> reporter: waide forced the 98-pound lea into the bag, covered her with trash bags, her legs dangling as he disrespected her for a final time. >> i took her out to the dumpster and i put her inside. >> reporter: leaving little doubt in the two-hour confession, his third in one day, police lock him up. >> we are going to be taking you into custody. >> i understand. >> reporter: and then they move to the search for lea's body, critical under colorado law for a first degree murder charge. district attorney dave young. >> without the body, we can't put together what happened in

>> reporter: police are sent out to track the only clue they have. waide says he put her in a dumpster next tois apartment. lea's mother lea's mother took us to it. >> he says he put her body in this dumpster right here. >> reporter: this awful blue dumpster has become the emotional center of the case for mother rene. >> i do have a pull to this place. whenever we've conducted searches in this area, i have to come here first. because this was the last place my daughter was. >> reporter: detectives track the trash, find the huge landfill near the denver airport, very close to the location where lea's phone last pinged. >> 40 days of searching, 40 days of hope, 40 days of going, you know, every day hoping that you're going to find a bag with a body. it's pretty depressing.

>> reporter: you wanted the body. >> absolutely. we need the body. >> reporter: the 40-day search was not a total bust. evidence -- strong evidence -- was found three weeks in. >> day 19 of this search was probably the most important day. one of our officers ends up finding a single purple pillowcase. >> reporter: inside, lea's cell phone, now smashed by the compactors at the dump. her wallet and i.d., clothes she was wearing. she had it all dry cleaned and put in a box. >> this was >> this was her bag. this was one of the things i bought her for her last christmas. >> reporter: this must be difficult. >> it's very difficult. it's the last thing of my daughter i have until i find her. >> reporter: frustrated and not anxious to take the case to the jury without lea's body, the prosecution tries a long shot,

second degree murder in return for that critical piece of information. where is lea's body? >> i called the defense attorney at least two or three different times saying, "i want to know where that body is. if he didn't put the body in a dumpster, we need to know now." >> reporter: but after the paperwork is signed, waide simply repeats what he said during interrogation, leaving tough questions for the prosecutor. why is the deal still good? why not throw the deal out the window and say, "we didn't get the body"? and say we can prove that this man's lying to us. we want you to reject this plea bargain. there's no way we can prove that. >> reporter: it's a deal rene jackson never liked. she rejects that this could have been an accident and thinks waide had been fantasizing about raping and killing a young woman for years. >> i >> i always keep these, the original charges.

charges. she has been discarded somewhere. and i feel that way because i know his history. >> reporter: a history confirmed in the police reports. listen to what waide's own mother told police during their investigation. she actually admits waide told her he had planned a murder before. >> he said that he went out one night to some girl's trailer with the intention of kidnapping her. >> reporter: waide's military records indicate it's fantasies like this that got him discharged from the army. >> they thought that he was going to go cause the death of a girl. >> reporter: so people knew in advance, and didn't act. >> yeah. i mean, they just dropped the ball all over the place. and then my daughter was his victim. >> reporter: when we come back, a field trip. destination -- sterling correctional center in northeast colorado. chris waide's had about a year now to think about the story that got him locked up in prison

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>> it was ju >> it was june 2nd of 2014. >> reporter: over and over waide stuck to his story, that the 98-pound lea attacked him with a knife he kept by the bed. you could easily take, either take the knife away from her, throw her to the bed and run, do anything short of killing her. >> and i will admit that that is what i should have done. >> reporter: waide agrees his story may not make sense, and admits to one glaring inconsistency. remember the 911 call from the park where he confesses foth second time? he does not call it an accident then. >> 911. >> yes, i'd like to confess to a murder. >> reporter: you knew the difference between saying, "i killed her" and "i murdered her?" >> yes. >> reporter: your first words to 911 are "i've murdered somebody." >> yeah. >> reporter: waide says he didn't want to inflame lea's brother who had just punched him by calling her death accidental. but why did he confess at all?

that my guilt over that would destroy me unless i let it out. >> reporter: and he says those cards also told him to kill himself. he never told police this or maxx. but his plan, he says, was suicide. >> the reason that i didn't commit suicide was that lea's spirit came to me and told me not to. >> reporter: but even with all that guilt and his year in finding lea's body. >> i've told the police what i did with her body, which was to throw it in the dumpster. >> she doesn >> she doesn't deserve to be just tossed away like a piece of trash. >> reporter: waide denies studying criminology to commit the perfect murder. but says it did help him a bit in the interrogation room. >> i kind of >> i kind of knew what to expect

professor at the storefront college, robert wells, isn't buying it. >> his efforts to clean and purge the crime scene, those are things he could have learned right there in my class. >> reporter: this hits you hard that he may have learned something in your class. >> how could it not? >> reporter: for two years rene jackson has not given up. she is still searching with little help for her lost lea. just 98 pounds in life, but a heavy weight on her heart and soul now. >> i look forward to the day that i get to meet my daughter. but in the meantime, i'm going to try to find her. >> that mother, still searching. our question, could you have done what that heroic brother did, playing it low-key while trying to get the confession some. >> let us know, using #abc2020. i'm elizabeth vargas.

thanks for watching tonight, and have a great weeke . working against the clock to find a missing boater and why they believe the man may still