lisa stabbed. >> the blade was actually bent. it takes a lot to bend a knife blade. >> the killer, none other than sabrina. >> i couldn't believe it. >> a loving mom murdered by the foster daughter she opened her home to. what no one could understand why? >>ing? else happened here. >> stories of a diabolical plot brewing behind closed doors. >> this was really just betrayal on top of betrayal, isn't it? >> obsession that would not be denied. >> it was like i want this -- this is how i'm going to get it. ♪♪ welcome to "dateline." police knew who killed lisa, but this case would prove to be anything but straight forward. it is not a who done it, but a why done it. the investigation unlocking a deep secret and a darker plot that anyone had imagined. here is josh mankiewicz with deadly betrayal. >> there comes a time in most cop's careers when they see something so horrific they'll do just about anything to forget it. even though deep down they know they never will. for officer randy, that moment came in november, 2012, on a call to shagrin drive in willow by hills, ohio. >> you ever have a seen like this before? >> never. i never seen a crime scene like that and i hope i never do again. it was bad. >> finding out what happened that night and why would ultimately lead investigators on a journey that would reveal accusations of a diabolical murder plot and a series of betrayals that tore apart an american family. that journey would begin when this house of horrors was still the loving home of lisa and kevin, a couple whose friends describe as destined to be together from the moment they met. >> i remember her talking about him and she had nothing but great things to say. >> lisa's close friends were the unofficial chaperons of lisa and kevin's first date. >> we got along right away. >> i mean, he fit right in, seriously. i could totally see why she was drawn to him. you really can. >> kevin was just as drawn to lisa, according to kevin's sister. >> i remember kevin telling me they met somebody. and her name is lisa and i think i really like her. >> both kevin and lisa had been married before and both had children. lisa had megan. kevin had cody. >> kevin was always good with children. >> linda is a family friend whose known kevin all his life. >> good father? >> good father. >> dedicated father. >> absolutely. absolutely. >> kevin was a jack of many trades. a truck driver, a school bus driver, an emergency medical technician. lisa dedicated her life to social work, helping and caring for sexually abused kids. cay lean was one of lisa's co-workers. >> she just wanted to help people. we work in the sex abuse unit. that's a very difficult subject a lot of people can't deal with but she really prided herself on helping these families and being able to help make a difference. >> everyone admired lisa's selflessness. her friend kari ward also worked with lisa. >> she took in foster kids while she was a single parent. was raising her own daughter by herself. >> that feels like sort of going the extra mile and then some. >> she did. she was always there to help anybody that needed it. >> admirable. >> yes, very much. >> one year after kevin and lisa met, they married. a year and a half later lisa and kevin announced the arrival of a baby of their own, hailey. lisa was on top of the world. >> megan loved like crazy, of course. but she really wanted another child. >> but lisa felt she had more to give. two years after hailey's birth, she decided to invite 16-year-old foster child sabrina into her home. and to make sabrina part of the family. >> i met sabrina almost immediately when she came to the house. i remember saying, i finally have a family. >> everything was going really well. she fit right into the family. lisa couldn't talk highly enough about her. >> but the happy times for the blended and extended family would come to a catastrophic end on that november night back in 2012 when lisa was brutally stabbed in her home. >> when i heard it was lisa and who did it, i couldn't believe it. it's like, you're kidding me? a devoted mom, attacked in her own home, enough to stun any family. but a crime this vicious, the first responding officer arrived to a frantic scene. coming up -- >> the blade was actually bent. i just started shaking my head because i couldn't -- takes a lot to bend a knife blade. >> who could have felt enough rage to do that and why? when "deadly betrayal" continues. "deadly betrayal" continues. cough cough sneeze sneeze... [ sneezing ] needs, plop plop fizz fizz. alka seltzer plus cold relief. dissolves quickly. instantly ready to start working. so you can bounce back fast with alka-seltzer plus. now available for fast sinus relief. ♪ ♪ ♪ (sha bop sha bop) ♪ ♪ are the stars out tonight? (sha bop sha bop) ♪ ♪ ♪ alexa, play our favorite song again. ok. ♪ i only have eyes for you ♪ the love and hope that the newly blended family vanished forever on a cold november night in 2012. >> 911, what is your emergency? >> pleads. don't. don't. >> at about 1:00 a.m., the police received a 911 call from the house. the caller was the 13-year-old daughter, megan. she said her mother lisa was being brutally stabbed right before her eyes. >> stabbing my mom with a knife. >> who has a knife. >> i have a female yelling on the phone someone else has a knife. >> megan was screaming, yelling at somebody to stop, you're killing her. stop. you're hurting her. why are you doing this. >> oh my god, my mom's gonna die. >> in the background, lisa can be heard, pleading for help. >> call 911. >> what is going on? >> oh my god. >> it's really chilling to listen to. >> you're going to have to take a deep breath. i cannot understand you. >> my mom's gonna die. >> first responding officer randy arrived at the home. and found megan frantic at the front door. >> she's waving her hands, you need to hurry, hurry, hurry. >> they learned kevin was away on business, leaving lisa, megan, hailey and their foster daughter sabrina at home. >> worst case scenario was going through my head. what am i going to see? how bad is this going to be? >> it was far worse than he could have imagined. out of the master bedroom came the 18-year-old foster daughter sabrina holding a knife. >> it looked like she literally showered in blood. >> he ordered sabrina to the ground where she was cuffed. he then went to the bedroom where he found lisa on the floor. >> i could barely even see flesh color. it was -- there was that much blood on her. i knew there was nothing i could do. >> the coroner would later determine lisa had been stabbed and cut at least 178 times. sabrina's weapon was a 15 inch bread knife. >> the blade was actually bent. i just started shaking my head because i couldn't -- takes a lot to bend a knife blade. >> with sabrina booked and in the lockup, detective ron began the investigation. >> it was a case in which you had to wonder who was responsible? >> that's correct. knew right away it was the foster daughter. >> this looked like a case that could be shut as quickly as it opened, but if that were true, we wouldn't be telling you this story. this turned out to be one of the most unusual cases we've ever come across. police would end up investigating not just who but why. with answers as stunning as they were disturbing. as dawn broke that cold november morning, detective began with his perpetrator, sabrina. >> i first noticed that she was very small girl, very frail girl. >> sabrina started describing the moments leading up to the murder. she had had a migraine, she said, while everyone else slept, she walked into the master bath to get some ibuprofen and that she said is where her memory went blank. >> you didn't think anybody could stab someone that many times and not remember any part of it. >> no. i tried all different ways to get her to come out and tell me what really happened. and she was not giving it up. >> and then sabrina asked for an attorney, bringing the investigation to an abrupt and frustrating halt. >> you thought, whatever else we're going to get is not going to come from her. >> exactly. >> so he consulted those who arguably knew this teenage ward of the state better than anyone, sabrina's social workers. >> she had some issues with her family growing up. her grandma took custody of her about the age of 3. >> case manager nicole said sabrina struggled with having been abandoned by her parents at a very early age. she ended up in the juvenile system after stealing from her grandmother to pay for drugs and alcohol. >> she worked a lot in counselling, how to cope and how to manage with everything she was going through. >> eventually, nicole helped place sabrina in the knafel home. >> she wanted to be a part of something, a part of a family. i know that's what she wanted more than anything. when she was told about being placed, she was ecstatic. >> it turns out the loving care was just what sabrina needed. >> she was going to class, getting good grades. i think sabrina really was thriving in their home. >> which made the news that it was sabrina who had brutally stabbed lisa all the more baffling. >> i still can't see the sabrina that i know being violent towards anyone let alone what she did. something else had to have been at play here. >> the detective was thinking the same way. he wanted to talk to kevin about what that something else might be. but he held off. >> i was giving him his space because i thought he needed time to deal with the tragic death of his wife. >> according to his sister, chris ann, kevin was an emotional reck when he heard what happened. >> i'm sure that there was some guilt because he worked nights and he wasn't home. he's like, i never thought this would happen. >> did you think he had anything to do with this? >> no. >> and you could definitively prove that kevin wasn't even in the house at the time. >> absolutely. kevin was on the ohio/michigan border at the time. >> still, the detective felt kevin might hold the key to solving the riddle of this case. why keep going? you got your suspect and she's got the weapon in her hand? >> just doing my job as a detective. i was trying to find out why. >> it was the one central question that continued to plague the detective and drive him forward. >> you're crossing your fingers and thinking, we need a break. >> yes. >> and then one day it arrives. >> one day sabrina decides that she wants to tell us what happened. >> and the story sabrina ultimately told was far more complicated and twisted than anyone could have imagined. coming up -- investigators hear stories about tensions in the seemingly happy home. triggered by sabrina's odd behavior. >> it made lisa uncomfortable. >> lisa wasn't happy with it, no. >> when "deadly betrayal" continues. dly betrayal" continues. hey hun hey, get your own vapors relax with vicks vapobath or with vicks vaposhower. take a soothing vicks vapo moment wherever you chose. well, would ya look at that! it was an accident. i was— speaking of accidents, we accidentally left you off the insurance policy during enrollment, and you're not covered. not even a little bit? mm-mmm. no insurance. no. when employees can't enter and manage their own benefits enrollment information, it can be a real pain. not even— nope! with paycom, employees enter and manage their own hr data in a single, easy-to-use software. visit paycom.com and schedule a demo today. small businesses like yours make gift-giving possible. now, comcast business has an exclusive gift for you. introducing the gift of savings sale. for a limited time, ask how to get a great deal for your business. and get up to a $500 prepaid card with select bundles when you switch to the network that can deliver gig speeds to the most businesses. or get started with internet and voice for $64.99 per month with a 2-year price guarantee. give your business the gift of savings today. comcast business. powering possibilities. news of lisa knoefel's bloody murder cut through ohio like a blistering winter wind. >> i was shocked. lisa was a nice person. she was a good mom. she was a good wife. >> for someone of that much beauty and that much giving of herself to just be taken from us like that, it's just too much. >> finding out that the foster daughter lisa welcomed into her home ended up committing lisa's murder only added to the collective pain and suffering. >> betrayal is the perfect word for what happened. somebody hurting her that she had taken in, i just can't even imagine what she must have been going through. >> as detective ron worked the case, he learned there had been growing tension within the knoefel home right before the murder. and the source of that tension was sabrina. >> she got along great with kevin and she did not get along well at all with lisa. >> detective discovered lisa had become frustrated with sabrina's behavior toward kevin. >> she was fascinated with kevin. she seemed a little vivacious in my eyes, flirty. >> uh-huh. >> like flaunting herself. >> and the detective learned from texts on lisa's cell phone that sabrina's flirty behavior had begun to take its toll on lisa and kevin's marriage. kevin was making himself available, too available as far as lisa was concerned. >> you have one actual text from lisa to kevin in which she's saying you're getting too close to sabrina. >> yes. >> in fact, lisa wrote, cut the damn cord. spending too much time with her and less with your real family. thanks a lot. lisa also became concerned about the relationship sabrina had with her daughter hailey. >> she acted like a mother to hailey on a regular basis. >> it made lisa uncomfortable. >> lisa wasn't happy with it, no. >> it sounds like one of the things that everybody agrees on is that sabrina was fixated on, fascinated with hailey. >> she was. i think she was infatuated with the whole family, and she wanted to be buy logically? that family. >> the detective learned that just weeks before the murder tension between lisa and sabrina had reached a breaking point. after 17 months under the knoefel roof, sabrina was told it was time to pack up and get out. >> sabrina got very upset, knew that lisa was the one initiating that action. >> and what, snapped? >> yes. >> but right now, all that was just a theory. then six months after the murder, the investigation took another turn. the detective learned sabrina was ready to talk. >> she starts telling her story. she starts sobbing. tears are coming down her face. >> sabrina told "dateline" the same story she told police, the story of a young girl bouncing through the foster care system, always dreaming of a better life. >> i wanted a new beginning. and to put all the past behind me. i wanted that picket white fence, the dinner on the table with siblings and you know something i never had. i wanted that structure of a family. >> so when the knoefel's opened their door to sabrina, it was a dream come true. >> my first impression of kevin was caring father, somebody that was willing to, you know, get to know me and want to know me. >> and then there was lisa. >> my relationship with lisa, it was at first good. we would all spend time together. we would go swimming in the backyard. i felt a part of the family. >> then sabrina confirmed what the detective had already heard. the good times quickly came to an end when sabrina and lisa started arguing. according to sabrina, lisa began thinking of her more foster than daughter. and sabrina didn't like that. >> i felt like the outsider. i felt kind of abandoned in a certain type of way. and not accepted. >> sabrina admitted her close relationship with both kevin and hailey had become a major source of friction with lisa. >> she doesn't like the fact of how i'm acting with hailey and wouldn't let hailey come around me. not even give me a hug at night. it really, it hurt me. >> then came the moment when sabrina said lisa told her it was time to go. >> she was very blunt about it. she was like, i'm sorry, i but i don't want you here anymore. my life was shattering before me. the betrayal. the abandonment. all that came to surface. >> two weeks later, sabrina says she quietly, carefully walked into lisa's darkened bedroom, a knife in her hand. >> i was in the room for a good 10, 15 minutes. it was a constant bat until my head. just do it. don't do it. just do it. >> in the end, it was sabrina's darker side that won out. >> she wakes up and she thought i was megan. and was like, megan, go to bed. i completely froze. and then she sits up in her bed and she was like, megan go -- and she realized it wasn't megan and that's when i did it. i remember her shouting bri stop and i remember megan coming in and setting a hand on my shoulder and said bri stop. i nudged her off. megan, don't. >> anger triggered by a troubled teenager's feeling of abandonment leading to murder. for the detective, sabrina's story made perfect, if tragic, sense. >> you believed sabrina. >> absolutely. >> but sabrina was not done. what she was about to reveal would send this investigation hurtling in a completely new and alarming direction. sabrina told the detective, she didn't act alone. >> i couldn't have done something like this if i didn't have another influence. coming up -- sabrina drops a bomb shell, claiming that getting rid of lisa was actually someone else's idea when "deadly betrayal" continues. honey? yeah? i respect that. but that cough looks pretty bad... try this robitussin honey. the real honey you love... plus the powerful cough relief you need. mind if i root through your trash? now get powerful relief with robitussin elderberry. and that's just basic wavy guy maintenance, right? next up, carvana. oh, boy. carvana just doesn't seem to understand how the test drive works. they give their customers seven days. and if they don't like it, they give 'em their money back. wait, they take the car back? that's crazy! what if it was driven by like a zookeeper? or a mud wrestler? or a guy who's on the outs with the missus and he just needs a place to sleep for seven days? yeah. (vo) buy your car online. love it or return it. with carvana. facing expensive vitamin c creams with dull results? olay brightens it up with new olay vitamin c. gives you two times brighter skin. hydrates better than the $400 cream. do you struggle to fall asleep and stay asleep? qunol sleep formula combines 5 key nutrients that can help you fall asleep faster, stay asleep longer, and wake up refreshed. the brand i trust is qunol. feeling sluggish or weighed down? it could be a sign that your digestive system isn't working at it's best taking metamucil everyday can help. metamucil psyllium fiber, gels to trap and remove the waste that weighs you down. it also helps lower cholesterol and slows sugar absorption to promote healthy blood sugar levels. so you can feel lighter and more energetic metamucil. support your daily digestive health. and try metamucil fiber thins. a great tasting and easy way to start your day. here is what's happening. cnn fired anchor chris cuomo on saturday following the suspension earlier this week. the network pointed to new information that surfaced about his involvement in the defense of his brother andrew cuomo, the former governor of new york. and the parents of teenager accused of killing four students at high school in michigan have pleaded not guilty to the involuntary manslaughter charges they face following the shooting. they were arrested early saturday following a man hunt. now back to "dateline." ♪♪ welcome back to "dateline" i'm natalie morales. sabrina zunich confessed to fatally stabbing her foster mom, and now the killer had even more to reveal, claiming she didn't act alone. continuing with "deadly betrayal" here is josh mankiewicz. >> detective ron parmertor always knew who killed lisa knoefel. and now he thought he understood why. interrogatory had told parmertor lisa was about to crush her dream of remaining part of the knoefel family. >> she hated lisa. >> feels to me like a motive. >> absolutely. >> i hated lisa. but it was only because she was triggering a lot of past issues. >> but there was more. there was, said sabrina, someone else. >> it's not all my fault. now, i take responsibility because i did what i did and i know it was wrong. but if it weren't for him, it would not have happened. >> if it weren't for him. sabrina was referring to her foster father, kevin. >> i was doing what kevin told me to do. that's what it comes down to. >> it was an astonishing accusation. sabrina told parmertor kevin had grown to hate lisa even more than she did. it was a feeling she said kevin shared with her slowly over several months. >> started through text. man, i wish she -- i wish she was dead. or i can't stand her. she just needs to go. >> according to sabrina, kevin also revealed that lisa had multiple life insurance policies and that she was worth more dead than alive. you had sensed for a long time that there was something going on that sabrina wasn't talking about. >> uh-huh. >> did you think this was it. >> didn't think it was this involved. >> but just as it seemed sabrina's story couldn't get any more twisted, she dropped a second bomb shell. >> her story was that kevin and her were having a sexual relationship and it was going on for probably about six to eight months prior to the homicide. >> i absolutely fell in love with him. >> kevin, sabrina said, promised her the world. and played on her love of 3-year-old hailey. >> he promised me we were going to have our own house and i could take over the role for hailey, you know, a mother figure. and i would go to college, do everything that i ever wanted to do in life. >> and then she said, kevin finally convinced her the only way to realize that picket fence dream was to kill lisa. >> it just started getting more concrete, more of you want to do it? you know? this is what we could have if, you know, if we do this. when you're in love, you will do anything for that person. >> according to sabrina, they first discussed the idea of sabrina shooting lisa. then they considered hiring a hitman. then after several months they finally settled on sabrina stabbing lisa in her sleep. >> kevin picked out this bread knife and it was about a foot long and it had a rigid blade. and he said to use this one because it would do more damage on the inside. i was supposed to take her ring, her necklace, all of that as if someone came in and burglarized her. >> are you kidding me? >> when kevin's friend linda got wind of sabrina's story, she was dumbfounded. >> i thought that it was absolutely crazy. there is no way -- i can't even believe that he would begin to do anything like that. >> neither could kevin's sister chris ann. kevin, she said, loved lisa too much to want to harm her, nor would he ever do anything to risk the safety of his children. >> he would not put his kids in harm's way. and i include megan in that. he thought of megan as his own daughter. >> no one, she said, could be manipulated into committing such a violent act. >> this is the act of one person and one person only. >> according to linda, sabrina's story was a web of lies. woven together by a deranged and troubled teen. whose fantasy of having a life with kevin and hailey pushed her over the edge. >> i think she imagined the relationship that didn't exist. it was like i want this so this is how i'm going to get it. >> as for the alleged affair, you ever see any hint of anything inappropriate between kevin and sabrina? >> absolutely not. >> no. no. that's not my brother. >> sabrina, they said, turned on kevin and blamed him for everything hoping for a plea deal. so what's going on here? sabrina lying to save her own skin? >> absolutely. absolutely. >> not according to detective parmertor. >> you're convinced there really was a plan between her and kevin? >> yes. >> and there was an affair despite the lack of hard evidence. >> she had no proof. there's no love letters. >> no. >> there's no photographs. there's no video tape. >> no. >> how do you know it happened? >> took sabrina on her word. every time we interviewed sabrina, she always told us the same story. >> and it rang true. >> absolutely rang true. >> and parmertor said he was suspicious of kevin even before sabrina came forward. several weeks after the murder, parmertor asked kevin to come to the station for an interview. kevin brought along his attorney. >> he would only answer the questions about his wife's work. >> and nothing about the murder. >> nothing about the murder. >> parmertor also became suspicious how kevin began filing claims for lisa's $080,000 of life insurance within hours of lisa being pronounced dead. and then he started spending the money. >> he was buying cars. he was buying a camper. he was remodelling his house inside. >> all with lisa's insurance money. >> all with lisa's insurance money. >> all of that was enough for detectives. three months after sabrina accused kevin of manipulating her into killing lisa, detective parmertor arrested kevin and charged him with plotting the murder. sabrina agreed to testify as the state's star witness. in exchange, the district attorney's office agreed to recommend that sabrina receive a reduced sentence. >> you're taking the word of an admitted murderer here. >> correct. >> even though she clearly got a reason to lie about this. >> yep. i believed what she was telling us was the truth. >> but would a jury agree? coming up -- testimony that kevin had talked about divorcing lisa and wanting sabrina to live with him. >> i thought it was a little odd that he wanted to take 17-year-old girl alone in a home with just him. >> when "deadly betrayal" continues. n "deadly betrayal" continues. nt has your moderate to severe eczema or atopic dermatitis under control? hide my skin? not me. by hitting eczema where it counts, dupixent helps heal your skin from within keeping you one step ahead of eczema. hide my skin? not me. and that means long-lasting clearer skin... and fast itch relief for adults. with dupixent, you can show more skin with less eczema. hide my skin? not me. don't use if you're allergic to dupixent. serious allergic reactions can occur, including anaphylaxis, which is severe. tell your doctor about new or worsening eye problems, i believed what she was telling >> when "deadly betrayal" i believed what she was telling >> when "deadly betrayal" or a parasitic infection. if you take asthma medicines, don't change or stop them without talking to your doctor. when you help heal your skin from within you can change how your skin looks and feels. and that's the kind of change you notice. talk to your eczema specialist about dupixent, a breakthrough eczema treatment. we're eating and drinking foods and beverages that are very acidic. talk to your eczema specialist about dupixent, it can soften the enamel. pronamel repair, what it's doing is driving more minerals deep into the enamel surface, that's going to help actively repair. pronamel is taking it to another level. your eyes. beautiful on the outside, but if you have diabetes, there can be some not-so-pretty stuff going on inside. it's true, with diabetic retinopathy, excess sugar can damage blood vessels, causing vision loss or even blindness. so remember this: now is the time to get your eyes checked. eye care is important to your long-term diabetes management. see a path forward with actions and treatments that may help your eyes— and protect against vision loss. visit noweyesee.com and take control of your sight. trelegy for copd. [coughing] ♪ birds flyin' high, you know how i feel. ♪ ♪ breeze driftin' on by... ♪ if you've been playing down your copd,... ♪ it's a new dawn, it's a new day,... ♪ ...it's time to make a stand. start a new day with trelegy. ♪...and i'm feelin' good. ♪ no once-daily copd medicine... has the power to treat copd in as many ways as trelegy. with three medicines in one inhaler, trelegy helps people breathe easier and improves lung function. it also helps prevent future flare-ups. trelegy won't replace a rescue inhaler for sudden breathing problems. tell your doctor if you have a heart condition or high blood pressure before taking it. do not take trelegy more than prescribed. trelegy may increase your risk of thrush, pneumonia, and osteoporosis. call your doctor if worsened breathing, chest pain, mouth or tongue swelling, problems urinating, vision changes, or eye pain occur. take a stand and start a new day with trelegy. ask your doctor about once-daily trelegy, and save at trelegy.com. ♪♪ in the spring of 2014, kevin knoefel's trial began in lake county, ohio. the charges, complicity and conspiracy to commit aggravated murder. kevin was also charged with sexual battery relating to sabrina. >> she was the perfect patsy. >> young, impressionable. >> idealist. >> and anxious to have a guy love her. >> yes. >> and so he manipulated her. >> yeah. >> but there was no slam dunk. kevin denied all charges. and prosecutors acknowledged, their case was based primarily on the word of sabrina, a young woman with plenty of reason to lie. this puts you in a difficult position, it seems to me. i mean, you are defending the character of this cold-blooded murderer and the fact that she committed this murder is all on someone else. >> not necessarily on someone else but together with somebody else. she would never have done this by herself. >> without any direct proof of the alleged affair, prosecutors began by calling those who say they saw signs of inappropriate behavior between a foster father and foster daughter. sabrina's teacher, willy smith, described spotting kevin with sabrina at the school one afternoon. >> she moved toward sitting in his lap inside his legs. >> what did you do at that point? >> i did a double take kind of -- really? >> then nicole, sabrina's social worker/case manager, testified about a strange call from kevin just a month before the murder. kevin, she said, admitted his marriage to lisa was in trouble and said they were considering divorce. >> what was your retoox that statement? >> i was surprised. i didn't know they were even considering splitting up or divorce. >> kevin, she said, asked whether in a divorce he would be able to take sabrina with him as opposed to her staying with lisa. >> i just thought it was a little odd that he wanted to take 17-year-old girl alone in a home with just him. >> prosecutors next showed juror's cell phone activity. more evidence, they say, that indicated kevin and sabrina were having an affair. >> kevin was texting sabrina way more than he was texting his wife. >> substantially more. >> within a two-week period, kevin and sabrina texted and called each other almost 1500 times. that compares to just 200 calls and texts between kevin and lisa. >> prosecutors then turned juror's attention to kevin's behavior after lisa's murder. david struck was one of kevin's close friends. struck testified that kevin seemed desperate to visit sabrina in jail, just one day after the murder. >> he told me that he just wanted to let her know that he was still there for her. this was the person that had just killed his wife and i was shocked that he would want to have any sort of contact with her. >> according to karen, kevin's real reason for wanting to see sabrina was to keep her from talking to police. and telling them about kevin's involvement in the murder plot. >> the trip to the jail was certainly huge. >> as pleased as prosecutors were with their case so far, they knew it would stand or fall on how the jury responded to their next witness. >> you guys worried? >> i was worried. >> they listened. everyone listened. as sabrina told of the night she took lisa's life. >> i started to stab her. i just raised the knife up and went down on her. >> why is it that you can finally and brutally stab her repeatedly 178 times? >> because i was manipulated to do it. >> by who? >> kevin. >> what did you think? >> sabrina was a strong witness. >> i felt she did a good job. >> maybe so, but without anyone to corroborate sabrina's story, prosecutors feared the jury still wouldn't believe it or her. enter the next witness, sabrina's high school friend, autumn. autumn testified she had first-hand knowledge about the murder plan and kevin's involvement in it. >> there was a phone call that we had. she had asked me if i was able to get her a hit man. >> could you tell if there were any other people in the room at the time. >> yes. >> and how could you tell that. >> i could hear the defendant in the background talking. >> autumn then testified she and sabrina discussed the idea of paying the hitman by delivering drugs for him. that's when she said sabrina handed the phone to kevin. >> what did he ask you at that time? >> do you need me to take you to go run drugs? >> okay. what was that in reference to? >> the hit. >> autumn said she ultimately backed out of the plan all together. >> finally i said, sorry. i can't help you. i don't want anything to do with it. >> but autumn was willing to later help detective parmertor with his investigation. after hearing autumn's story, parmertor asked autumn to call kevin and talk about the hit man. thinking kevin might implicate himself. prosecutors played that recorded phone call in court. >> the only thing that i'm worried about is that whole hit man thing. >> i honestly don't know. she talked a big game about a lot of things. >> on the call, kevin never admits to knowing anything about a hit man, but the detective parmertor, his calm manner and apparent lack of surprise suggests a prior knowledge of the plot. >> never says what are you talking about? i've never -- we never had any conversations. if you have any information about the murder of my wife, please go to the police. never says anything like that. >> in fact, when detective parmertor called kevin just two days later, kevin made no mention of autumn's call. and claimed to have only a vague recollection of who autumn was. even though he just spoken with her. >> last name doesn't ring a bell, but i think she had a friend, um, named autumn at school. >> as prosecutor saw it, kevin was trying to keep police from finding the one person, other than sabrina, who could link him to lisa's murder. >> clearly a lie. very damaging. >> prosecutors were now confident jurors had all they needed to convict. but now it was the defense's turn to make its case. and kevin knoefel's attorneys weren't about to let sabrina leave that courtroom without a fight. coming up -- the defense tries to undercut the prosecution's whole premise, arguing there was nothing going on between kevin and sabrina. >> there were 12 witnesses that if they see any form of abuse they have a mandatory duty to report. >> and none of them did? >> and all of them testified they didn't do it. >> when "deadly betrayal" continues. >> when "deadly betra continues. just two pills for all day pain relief. aleve it, and see what's possible. and also try alevex topical pain relief. the new sensodyne repair and protect with deep repair has the science to show that the toothpaste goes deep inside the exposed dentin to help repair sensitive teeth. my patients are able to have that quality of life back. i recommend sensodyne repair and protect with deep repair. ♪ ♪ ♪ (sha bop sha bop) ♪ ♪ are the stars out tonight? (sha bop sha bop) ♪ ♪ ♪ alexa, play our favorite song again. ok. ♪ i only have eyes for you ♪ (cooking timer rings) ♪ this is how we do it ♪ ♪ this is how we do it ♪ (tools drop) (squeaking sound) ♪ this is how we do it ♪ turns out, montell jordan knows how to do almost everything. and it turns out the general is a quality insurance company that's been saving people money for nearly 60 years. ♪ this is how... ♪ i got it, i got it, i got it. for a great low rate, and nearly 60 years of quality coverage make the right call - and go with the general. for rob, it took years to find out why his constipation with belly pain just wouldn't go away. despite all he did to manage his symptoms... day after day. still came the belly pain, discomfort, and bloating, awful feelings he tried not showing. finally with the help of his doctor it came to be, that his symptoms were all signs of ibs-c. and that's why he said yess to adding linzess. linzess is not a laxative. it helps you have more frequent and complete bowel movements, and is proven to help relieve overall abdominal symptoms belly pain, discomfort, and bloating. do not give linzess to children less than two. it may harm them. do not take linzess if you have a bowel blockage. get immediate help if you develop unusual or severe stomach pain. especially with bloody or black stools. the most common side effect is diarrhea, sometimes severe. if it's severe, stop taking linzess and call your doctor right away. other side effects include gas, stomach area pain, and swelling. could your story also be about ibs-c? talk to your doctor and say yess to linzess. learn how abbvie and ironwood could help you save on linzess. kevin knoefel's defense attorney mike conic felt pretty confident as he prepared his counterpunch before the lake county court. did kevin have anything to do with lisa's murder? >> no. >> did he have any sexual relationship with sabrina? >> no. there was not one san till la of physical evidence to tie kevin to any of these crimes. >> conic began trying to dismantle the evidence the state did present. he challenged the county employees who had testified they believed kevin was acting inappropriately towards sabrina. asking why they didn't report such behavior before the murder. >> at that time, did you have a serious concern, you would have filed a report, wouldn't you? >> i would have filed a report if i felt it was a serious concern. i did not file a report on this. >> there were eight, ten, maybe 12 witnesses that are mandated reporters. if they see any form of abuse, they have a mandatory duty to report it. >> and none of them did? >> and all of them testified they didn't do it. >> no one reported inappropriate behavior, said conic, because there was nothing to report. >> lisa ironically was a mandated reporter. she never reported it. >> conic then addressed the large number of texts between kevin and sabrina. >> i don't find that shocking. >> neither did kevin's sister, chris ann. >> there's more texts between my husband and one of my daughters than my husband and me. it doesn't mean anything. >> but what about those who testified kevin acted suspiciously immediately after the murder? >> i don't think i would want to have to come home and find out that my wife was butchered and have other people criticize what my emotional response was to that situation. >> kevin's friend linda agreed. even if the emotional response was to try and visit sabrina in jail. just one day after she murdered kevin's wife. >> i thought about that. and i'm thinking he might have want to say why in the hell, what's the matter with you? >> linda also believed kevin was unfairly judged for filing the life insurance claims as quickly as he did. kevin, she said, had to think about the welfare of his children. >> now i have to be the sole support. now what am i going to do? >> great deal of the state's evidence were witnesses said he's not acting the right way. he's not acting normal. as soon as somebody can tell me what normal is, i'll be happy to adopt it as a notion. >> conic applied that same argument to the criticism of kevin's muted response to the mention of a hit man on autumn's recorded phone call. >> what was he supposed to do? be angry? was he supposed to be defensive? if he had -- >> i think what he was supposed to be was something. >> that's kind of kevin's demeanor. you can't pass judgment on that. >> but what about autumn's testimony that she spoke directly to kevin about hiring a hitman to kill lisa? conic dismissed that testimony as being inconsistent and unreliable. during cross, conic asked autumn to read a transcript of her initial interview with police when she was asked if kevin was ever a part of her conversations with sabrina about trying to hire a hit man. >> why don't you read me your answer on page 32 at line 3. >> no, well, no. we were on the phone and she didn't really talk about it in front of him. and i don't think he knew that i knew. >> thank you. nothing further. >> she ultimately acknowledged that kevin was never present or on the phone during those conversations about killing lisa. >> but mike conic knew it would be his cross-examination of sabrina that would determine kevin's fate. >> i represent kevin knoefel. >> hello. >> sabrina is a seriously disturbed human being. >> the murder itself, he said, was all the proof the jury would need of that. >> do you recognize this identify? >> yes. >> and when you began slaughtering lisa knoefel, this knife was straight, wasn't it? >> yes. >> and you attacked her with such vigor and force, anger and rage, that you managed to put a 20 degree bend in a stainless steel knife, right? >> conic continued pressing, hoping to show sabrina was motivated not by manipulation from kevin but by her hatred for lisa. >> you used the abandonment as a rational for it to be okay for you to murder my client's wife. >> no, i did not. >> correct. >> no. it was a factor that came into it, yes. a justification, a rationalization, no. >> in the end, sabrina never wavered from her story. still, conic felt he damaged her credibility. >> by the conclusion of her testimony, there should have been no question that she was not reliable. >> but that was for jurors to decide. it took them just under ten hours to deliberate. >> we have a verdict. >> guilty on all counts. >> guilty of sexual battery as charged in the indictment. guilty, of conspiracy to commit aggravated murder. guilty of aggravated murder as charged in the indictment. >> kevin knoefel was sentenced to life in prison and at the time linda had this to say -- >> you think an innocent man is in jail. >> absolutely. absolutely. i mean, i would about stake my life on that. >> sabrina also received a life sentence but will be eligible for parole in 30 years. as recommended by the state. prosecutors feel justice was served. but lead prosecutor karen is quick to point out cases like these bring little satisfaction. this was really just betrayal on top of betrayal on top of betrayal, isn't it? i mean, you got kevin betraying lisa. sabrina betraying lisa. then ef kevin betraying sabrina . >> yeah, it's a perfect circle. that's all for this edition of "dateline" i'm natalie morales. thank you for watching. not for long, i think my wife is having a stroke. an hour later she's back at the hospital she just left. she had this blank stare and her eyes. three days later, she was that.