>> this is a small town whodunit. >> oh, yeah we were afraid. >> what had happened that night? was the answer somewhere in her circle of friends? >> we're trying to find out why! >> i would never hurt halee. >> they came and talked to me. it was four fbi agents. >> he's there. he's got a gun. >> how could it not have been him? >> then a secret spills out in court! >> that's a bombshell. >> that definitely was. >> i felt like i had gotten my heart ripped out. >> for that mother to get on that stand. it was absolute silence. >> hello and welcome to "dateline." halee rathgeber was barely out of her teens. halee enjoyed taking care of others. it made sense to them she was studying to become a nurse. what made no sense was that anyone could want her dead. the crime scene told investigators little, but a jaw dropping moment in the courtroom spoke volumes. here's "on the outskirts of town. " >> i'm miles from my family in new york. but i'm driving, oddly enough, through a place that feels like home. quaint downtown the kind of place you feel safe. this is newburgh in southwest indiana. you can see the early days of the midwest in these historic buildings. open farmland everywhere. hometown usa, a place for putting down roots. >> turn left on county 45 west, then your destination will be on the left. >> and there it is. what i've been looking for. a gravel lot by a soccer field. a spot to play sports. to hang with friends. not a place for a young woman to die. it's jarring to think that when a life ends, so much begins. a family's grief. a community's shock. and in this case right here where i'm standing a murder investigation. heather collins has always been proud of her three girls, especially her oldest daugher halee, who even at a young age was eager to lend a helping hand. >> there's you know so many pictures of her holding the baby sister, you know, and just taking care of them. yeah. she's always leading the way. >> my kids, they you know, they wanted to feed the bottle and, "can i change a diaper? " >> uh-huh. she was the best diaper changer ever. >> a mother's helper and sister emilee's best friend. with halee, she says, she felt safe. >> she was always definitely what you pictured an older sister being like. like, the big protective, "don't mess with my sisters or i'll come at you" type sister. >> that protective streak continued all through school, even extended to friends. carley sollars and ansley bowles. >> she kind of just acted like everyone's mom because she was so caring. >> she was tall. and everybody, all of our friends are so short. and so it was always, like, she stuck out and we would go places and she would tower over all of us. it made it funny. >> the mom and all her kids. >> yeah. and so people always like, she was the first one that they noticed. >>the world was kind of like her catwalk? >> yeah. >> yeah, pretty much. >> beautiful girl? >> yeah. i love when i get told that i look like her. it makes me really happy. >> aww, that's awfully sweet. but halee's beauty was more than skin-deep. tattoos, like this one on her back, testified to her strong faith. >> i said prayers with the girls every night. tharon rathgeber is halee's dad. >> and at the end of our prayer the most important line was, "and those that are less fortunate than we are. " and i think she really grasped that. >> and drew strength from it, especially in difficult times. one night, in particular, was a defining moment for young halee. she was just 12 when she went to a friend's house for a sleepover. >> that night the brother of the girl that my daughter was staying with had a friend over. and he was 19. my daughter was 12. and he tried to molest her. >> at first, halee said nothing to her parents. but when she learned that the man had preyed on other girls, her instinct to help led her to act in a way few her age would have the courage to. >> she testified and sent him to prison. and after that i think that's when people realized they could always go to halee. that she would fix anything, and she would stand up for the weak. the less fortunate. it was no surprise, then, when halee announced she wanted to continue helping others as a nurse. after high school she enrolled at near-by university of southern indiana. i hear that the girl was constantly buried in a book. >> she worked really hard. >> where does that come from to just wanna study all the time. >> i don't know'cause i don't have it. she had so much drive and, like, ambition, and she knew what she wanted, and she was gonna have it. >> when she wasn't hitting the books she was waiting tables at the texas roadhouse. that's where she met and started dating isaiah hagan, a shy, fellow waiter. >> he seemed really nice to me. and he seemed to let halee do her own thing, which i liked. >> how did you feel when you saw them together? did they seem like a good match? >> yeah. i mean, they weren't lovey-dovey at all, which i prefer, to be honest. he joked with us. he actually took an interest in talking to us, which is more than i can say for a lotta guys. >> the romance didn't last long, though the two remained good friends. besides, 20-year-old halee was laser focused on her schoolwork. on a sunday in late april 2017 she was home, studying for a big exam the next day. just hours later, the sun was rising and halee's mom heather was starting her morning. >> i was reading facebook, having coffee on a monday morning. just sitting on my porch and i scroll across a news article. >> it was shocking. police had found a body in a soccer field near newburgh. >> it says it's a young female, so i immediately start looking for the younger two, because they're in high school in newburgh. >> you just wanna make sure. just as a mom, "i just wanna make sure everybody's--" >> yeah. >>--"safe? " >> i just wanna find my kids. >> heather found her two youngest, they were ok. but halee wasn't answering her phone. and friends told heather she didn't show up to take her exam at the university. >> it's not like her to miss class. not like her to have her phone turned off. >> not like halee rathgeber to go missing. >> coming up, what had happened to halee? >> were you getting a sick feeling? >> i was sick all morning. it was so much anxiety. i started screaming her name. my stomach dropped. i was, like, where is halee? >> when "dateline" continues. rsv is in for a surprise. meet arexvy. ( ♪♪ ) the first fda-approved rsv vaccine. arexvy is used to prevent lower respiratory disease from rsv in people 60 years and older. rsv can severely affect the lungs and lower airways. arexvy is proven to be over 82% effective in preventing lower respiratory disease from rsv and over 94% effective in those with these health conditions. 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(vo) football season is here. get nfl sunday ticket from youtubetv on us. a $449 value. plus, get a free samsung galaxy z flip5. only on verizon. every day, businesses everywhere are asking: is it possible? with comcast business... it is. is it possible to use predictive monitoring to address operations issues? we can help with that. can we provide health care virtually anywhere? we can help with that, too. is it possible to survey foot traffic across all of our locations? yeah! absolutely. with the advanced connectivity and intelligence of global secure networking from comcast business. >> heather collins couldn't get it's not just possible. it's happening. the news out of her mind. that morning, april 24th, 2017, local police found the body of a young unidentified woman at a nearby soccer field. >> and, you know, immediately i'm worried about whose child this is. >> it certainly wasn't hers. at least that's what heather told herself, and yet, she was worried. she couldn't reach her eldest, halee, by phone. >> i called her friend ainsley and said, you know, "hey. have you heard from halee? " >> she's like, "i know you have her apartment key. can you drive over there and see what she's doing? " >> when ansley did, she saw halee's car parked outside the apartment, meaning halee must be inside. ansley put the key in the front door. >> i swung open the door. i was, like, "halee. " and i just started screaming her name. like, my stomach had dropped, and i was, like, "oh my god. " i was, like, "where is halee? " i was, like, "where could she be? " >> around the same time, halee's sister emilee was driving to work with a friend. suddenly, a sense of doom washed over her. >> i'm freaking out. something's wrong. >> just, like, out of the blue this feeling came. >> yeah, it was out of the blue. like, we were driving, and all of a sudden, i was just like, "you gotta turn around. i gotta go find my sister. something's wrong. like, i don't know what's wrong, but something's wrong. " >> emilee posted a picture of halee on instagram. "if anyone hears from my sister please contact me. " friends responded, telling her that police were trying to identify a woman found dead that morning. >> and that's when people started sending me that article. >> oh gosh. >> at the time i was just, like, "no, like, i get you're trying to be helpful. like, but that's not her. " like, and it wasn't even like i felt like i was in any denial. i just 100% knew that that was definitely not my sister. >> meanwhile, warrick county sheriff's detective paul kruse was just pulling up to the soccer field to begin his investigation. officers had already roped off the scene. when you pull up here what do you see here? >> there's a body. we got a body laying here with a terrible wound to the head. >> this is a very desolate area. i mean, i'm sure when people are playing soccer, it's active but -- >> sure. >> -- in the middle of the night there's nothing around here. >> this place is just pitch black in the middle of the night. nearest neighbor's probably a half a mile -- straight line away -- separated by trees and fields. >> even at a glance the detective could tell the woman had been murdered. left to die in agony. the coroner would later cite the cause of death as a gunshot wound. what did it tell you that she was shot in the back of the head? >> tells us that she knew and trusted the person she was with. >> could you get a sense of her last moments? >> unfortunately, the evidence here at the scene showed that she had lived for a while after being shot. >> you could see it in the gravel? >> you could. it almost looked like a snow angel where one of her legs had rubbed back and forth, and had rubbed a bare spot in the gravel. >> and this was odd. next to the woman lay a blue towel. other than that, there was little to this crime scene. >> did you find a weapon? did you find a bullet, a casing, anything that might help you? >> no. we had detectives actually assigned to get on their hands and knees with scissors and cut the grass away, looking for a shell casing -- >> wow. >> -- or a bullet or anything. and we have no idea who she is. there was no identification, no phone, nothing laying with her at that time to help identify her. >> but that mystery would be solved soon enough. heather, by now in a panic, called an old friend for help. >> i contacted a detective i knew from vanderburgh county and -- >> i mean, i'm getting chills right now. are you getting a sick feeling? >> oh, i was sick all morning. it was so much anxiety and i didn't know what to do, and i just kept thinking i'm wrong. >> she gave the detective halee's full name and description, and he forwarded the information to the warrick county sheriff's office. investigators there immediately checked facebook, where they found halee's profile and picture. >> and there was a tattoo visible. there was a tattoo visible on facebook, that matched. so, we were pretty certain at that point who our victim was. >> warrick investigators called heather collins and asked to speak with her in person. she walked into the meeting, dreading what they might say. >> they said you know "there's a body found, and -- you know, we've identified her as halee. " >> in an instant, your whole world is shattered. >> nothing was the same after that. nothing. >> every time i talk about it, just the pain comes, like, rushing back, like, how awful. i've never felt so awful. like, i just remember just -- i didn't wanna exist anymore. >> the family was horrified to learn that halee, just 20 years old, had been murdered with a shot to the back of the head. >> that was the most shocking part. never in a million years would i have thought that someone would shoot my child. like, why? >> as you're processing the most horrific news you've ever had in your life, that your daughter is gone, do you immediately ask these detectives who did this? >> they asked me. >> they asked you? who do you think? >> one name sprang to mind immediately. heather blurted it out. >> their eyes they couldn't believe what they were hearing. >> detectives knew that name, from another case. halee knew it too. coming up -- >> she said, what if they want to talk to me? i'm, like, you talk. >> had someone wanted to keep her quiet -- >> halee could be poking a hornets nest, if she starts making accusations. >> she absolutely could have. >> when "dateline" continues. but olay goes 10 surface layers deep. our clinically proven hydration beats the $500 cream. to strengthen my skin for smoother, brighter results. your best skin yet. olay. sometimes, the lows of bipolar depression feel darkest before dawn. with caplyta, there's a chance to let in the lyte™. caplyta is proven to deliver significant relief across bipolar depression. unlike some medicines that only treat bipolar i, caplyta treats both bipolar i and ii depression. and in clinical trials, movement disorders and weight gain were not common. call your doctor about sudden mood changes, behaviors, or suicidal thoughts. antidepressants may increase these risks in young adults. elderly dementia patients have increased risk of death or stroke. report fever, confusion, stiff or uncontrollable muscle movements which may be life threatening or permanent. these aren't all the serious side effects. caplyta can help you let in the lyte™. ask your doctor about caplyta find savings and support at caplyta.com. >> tharon rathgeber never thought he'd outlive his own daughter. >> when they, you know, said she'd been murdered, you know, i went you know, to the dark side. we all have. i wanted to kill myself.'cause i wasn't there to protect her, you see? >> it was hard for him to know how to move forward. but even in death halee was a comfort to her family. >> and the things that impacted us the most is her tattoo that had psalms 46: 5. and it was, "god is within her. she will not fall. he will help her at break of day. " >> it's just so difficult to imagine why any human would do something that horrific to another human being. >> detective paul kruse looked for answers with grim determination. halee's murder was not the only tough case weighing on him that april morning. a few weeks before, he and his partner were assigned to look into the suspicious death of a 10 month old baby named jaxon. when detectives spoke to heather after her daughter's death she revealed something that stunned them. >> halee was the godmother of jaxon. >> so their jaws dropped? >> yeah. yeah. >> heather told police baby jaxon was the son of halee's old school mate, jordan. >> she got a baby to play with without having to have a baby so. >> but then a terrible accident, jaxon had fallen down some stairs halee rushed to the hospital where jordan explained what had happened. her boyfriend a man named thaddeus rice had dropped the baby down the stairs after tripping over a diaper bag. >> jordan was crying and we, like, gave her a hug. and i looked at halee. and halee like looked at me and i was, like, "what are we gonna do? " >> they did what they could to help. they got jordan some food and went to her apartment to get her some clean clothes. >> we walked in and halee's, like, "do you know what's weird? " and i was, like, "what? " she goes, "the diaper bag is sitting right there. " like, as soon as you walked into the door, the diaper bag was sitting right by the couch. it didn't look like the diaper bag had fallen down the stairs, like what thad had said. >> so you're thinking, "we might've just caught thaddeus in a big lie? " >> yeah. >> after two days on life support, jaxon died. grief-stricken, halee agonized over whether she should tell police about her suspicions. >> she had said, you know, "what if they wanna talk to me? " i'm like, "you talk, " you know? >> but the more halee's mom thought about it, the more she worried what might happen to halee if she spoke out. thaddeus had a bad reputation around town. halee could be poking a hornet's nest. >> she absolutely could have. >> if she starts making accusations. now halee was dead. and heather wondered if her fears had come true had thaddeus killed halee to shut her up? >> i just felt like you know, he was looking at some pretty serious charges if i had to think of people who had reasons to hurt her, that would have been number one. >> the day after halee was murdered someone sent heather this snapchat video. it was thaddeus brandishing a gun. you got that video, so that must have really heightened -- >> oh, the video was -- >> -- your suspicion. >> huge. i was positive at that point. >> he did it. and heather wasn't the only one pointing the finger at thaddeus. halee's friends knew that she'd gone to see the baby's mom jordan the night she died. >> there's these messages the night she was murdered, where she was messaging back and forth with jordan, "hey, i'm gonna go pick up my wallet from your house" late at night the night she was killed. so then that was the theory, she wept, she told jordan, thaddeus killed her over it. >> investigators decided it was time to find out what thaddeus and jordan knew. thaddeus refused to talk to them. but jordan did. >> we did interview thaddeus'girlfriend. she was -- she said they were home together all night at thaddeus'brother's house. we checked out the surveillance video from that neighborhood. we were able to see halee come into the neighborhood when she was there to get her wallet, and we saw halee leave the neighborhood. but we never saw jordan and thad leave. >> it seemed like thaddeus had a good alibi. heather worried that investigators seemed no closer to making an arrest. >> i think that the fear was overwhelming. i kept saying, "i hope that they make an arrest before her funeral. i don't know how i can stand there and wonder who's hugging me and -- and who's coming through this line. you know, did they hurt her? " >> but as heather prepared for her daughter's funeral, investigators were already talking to someone who'd surely be standing in that line of mourners, someone very close to halee. >> take a seat over there. >> coming up, video from the night of the murder! police have a few questions for halee's friends. so were you thinking, "they think i might be involved? " >> yeah. >> when "dateline"