>> something was wrong. >> her daughter, away at college wasn't answering her phone. >> she was scared. she didn't know where alex was. >> then, terrible news. a student had been murdered. a young woman. but apparently, it wasn't alex. >> the girl laying on the floor had dark, almost black colored hair. she had much lighter hair. >> so who was it and where was alex? >> at that point, it was one dead and perhaps another missing. >> the killer could be roaming a campus full of students. >> we were really scared. >> a mysterious tweet. >> what do you think it meant? >> i don't exactly know. >> a terrifying phone call. >> my son just called. >> and a terrible truth. >> i didn't know how. i didn't know who. i didn't know anything. i just know she was gone. hello, and welcome to dateline. a college freshman found brutally beaten in her dorm room. a crime scene so bloody, police could not identify the victim, but identifying the killer was not nearly as hard. he admitted what he did, turning himself into police within hours. it was why he said he did it that would become the foundation for his defense. here's andrea canning with, after midnight. >> every year, as summer fades into fall, and lazy days at the beach come to an end, students flood back to college. it's the same scene year after year at campus after campus. and every year, there's that new bunch. the freshman. >> i was nervous for classes. >> all those worries, all those questions. >> do i really have to go to these classes and what's this teacher like? >> they are not quite adults. they are not quite teens. now, suddenly, they are on their own. >> leaving home for the first time can be scary. >> scary for the kids, for their parents, too. >> every mom has that, my baby is going to college. >> it's hard. >> yes. >> most of the times, kids sail through the experience. they make new friends. date new people, and move on. but there are others who are not so lucky. they are the victims of a troubling trend that caught the nation's attention. dating violence. >> it could happen to anyone's daughter. >> this could happen to anyone. >> it was late september, 2012. the college at brockport, the state school in e western new york was well into the new school year. 18-year-old alexandra was having the time of her life. >> as soon as i met her, i knew we were the perfect match for each other. >> alex and samantha turner met within days of arriving on campus. besties from the beginning. >> you really clicked with alex i? >> i did. >> why did you like her? >> i could act myself. if i had a problem, she was always there for me. >> by late september, alex and samantha were inseparable. swapping clothes and confidences. but on friday, september 28, they were going off in different directions. samantha was heading home to see her family. alex was staying on campus. counting the hours until her long-time boyfriend arrived for a weekend visit. that afternoon, alex went down the hall to samantha's dorm room to say good-bye. >> it was around 3:00 maybe, and i was about to go home and she's like, can i pick out some clothes in your closet? i was like, sure, she took three of my shirts and a pair of my shoes and she was all excited. clayton will be here in a half an hour. >> 21-year-old, clayton, was alex's boyfriend. he was coming to spend the weekend. but first, alex had a swim team meeting. she had been swimming since high school where paige whitney was the captain. >> you were the captain of the swim team, but you call alex more the heart of the swim team? >> definitely. in high school, she definitely wasn't the fastest on our team, but she was one of the most important people on our team, because she had the most heart. she would be behind you at every single one of your races cheering you on. wishing you luck. >> now, paige and alex were teammates again. >> she must have loved knowing she had you to lean on. >> i feel like there was definitely that sense of security. >> that friday, the team meeting ran late. alex's boyfriend got to town before it ended. alex texted to apologize that she wasn't there to greet him. please don't kill me, she wrote. no worries, he answered. soon, the two got together with a busy night ahead of them. midway through the everyoning, samantha texted alex. >> i told her, i was like, can't wait to see you tomorrow. love you, good night, you know, and then she said the same. >> but later in the early hours of saturday morning, samantha was awakened by a call. alex's mother was on the line. what in the world was up? >> she was scared. she didn't know where alex was, what she was doing. she had a sign. i don't know how. something was wrong. >> her mother just thought something was wrong and called you. >> yes. freaking out. i was like, i'm home, i don't know. >> a fearful mother on the phone in the middle of the night searching for her daughter. what happened to set her off? why was she so distraught? sandra whitney is a good friend of alex's parents, she is paige's mom. >> they had gone off for a weekend vacation and they had been texting that evening and becky t was sending her picture of their hotel room, you know, you get to a hotel, hey look. alex didn't respond. and she tried over and over again and she didn't respond. and that's not how their relationship worked. you text, you call, you always responded. >> is that llunusual that she wouldn't respond in college? it's a weekend. her boyfriend is coming for the weekend. >> i imagine the first couple times, maybe she wasn't concerned, but when it was several, that's what raised flags. >> a little bit of mother's intuition, do you think? >> i imagine it was. >> alex's mom worked the phone frantically trying anyone who might know where her daughter was. finally at 2:42 a.m., she called the campus police to ask her to go to her daughter's dorm room to check on her. officer michael johnson responded. >> you took that call? >> i did. >> you headed over to the dorm. >> yes. >> and then what happened? >> we went there. i knocked on the door. i knocked ketwice, and since it was a welfare check. i said let me see if this door is unlocked. >> it was, officer michael johnson will never forget what was inside that room. >> it just seemed that something really bad happened there that night. >> what had happened in room 108? police were about to confront a frightening and confusing scene. coming up -- >> you never come to work thinking you're going to see something like that. >> a young victim, but who is it? >> they are telling everybody, keep your door shut. we didn't know what was going on. >> when dateline continues. some things should stand the test of time. long lasting eylea hd could significantly improve your vision and can help you go up to 4 months between treatments. if you have an eye infection, eye pain or redness, or allergies to eylea hd, don't use. eye injections like eyla hd may cause eye infection, separation of the retina, or rare but severe swelling of blood vessels in the eye. an increase in eye pressure has been seen. there's an uncommon risk of heart attack or stroke associated with blood clots. the most common side effects were blurred vision, cataract, corneal injury, and eye floaters. and there's still so much to see. if you are on eylea or a similar type of treatment, ask your retina specialist about eylea hd today, for the potential for fewer injections. (luke) this will be a gold mine of local intel. just you wait. ask your retina specialist about eylea hd (marci) right. so, tell us about this corn festival? (stylist 1) oooh you got your corn pudding... you got your corn chowder... (marci) so... is it safe around here? (stylist 2) sometimes. (luke) if a family of eight were to need a cold plunge, where would they find it? (stylist 1) ...and then they dip it in butter, then bam, it goes right in. (stylist 2) ...really cute vampire bar. (stylist 1) the reverend does like a blessing on the corn. (luke) donut shops. how far from here? (marci) no eyebrows? (luke) think of how light it'll feel in the summer. we've got to run. eleven thousand more neighborhoods to go! (vo) ding dong! homes-dot-com. [coughing] copd isn't pretty. i'm out of breath, and often out of the picture. but this is my story. ( ♪♪ ) and with once-daily trelegy, it can still be beautiful. because with 3 medicines in 1 inhaler, trelegy keeps my airways open for a full 24 hours and prevents future flare-ups. trelegy also improves lung function, so i can breathe more freely all day and night. 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. ♪ what a wonderful world ♪ [laughing] ask your doctor about once-daily trelegy for copd because breathing should be beautiful, all day and night. choose advil liqui-gels for faster, stronger and longer-lasting relief than tylenol rapid release gels because advil targets pain at the source of inflammation. so for faster pain relief, advil the pain away. officer michael johnson, a cop at the college at brockport was on a routine welfare at a dorm room early saturday in september of 2012 when he got the shock of his life. >> we don't see that level of violence that often. >> room 108 was wrecked. there was blood everywhere. on the bed. on the door. on a pillow on the floor. in the center of the room was a young woman laying on the floor face down. her bloody hair falling over her face. >> it seemed very unnatural the way she fell. the blood splatter that was in the room. even the bloody footprints around her all indicated something violent happened in that room. >> what feeling do you have when you see something like that >> >> the adrenaline kicks in. you need that adrenaline. it was time to go to work. if she was alive, i had to do all i could for her. >> officer johnson knew he needed help fast. >> i heard this guy yelling and i thought it was a drunk college kid. >> hayley lived across the hall from alex's room. the commotion woke her up. >> i noticed a man was yelling for help and stuff. so i woke up and i started looking through my peephole and it was a police officer yelling. >> then lieutenant, daniel, worked with officer johnson on the campus force. >> he radioed me for the aed. that's the defiblator. so i arrived, i grabbed it. i went running to his location. >> what did you think when you saw what you said? >> i couldn't believe it. i guess you never come to work thinking you're going to see something like that. >> hailey was now glued to her peephole. she saw residence officials everywhere. >> they were telling everybody to keep your door shut. don't come in the hall. we didn't really know what was going on. >> the news was spreading. hailey was fielding a storm of texts from worried students. >> everyone was just so confused. everyone was like, i don't know. i think somebody is hurt. but i don't know what's happened. >> by now, the cops realize the young woman on the floor was dead. hailey soon learned that, too. >> what happened was, the ambulance showed up and the police officer said to the paramedic, we only need one of you to go in and to pronounce her. the paramedic went in and came out, pronounced her jane doe, and it was just like, oh wow. i knew that meant they couldn't identify who it was and they left. and i woke my roommate up and i said, you know, somebody died. and she didn't believe me at first. i told her, they left. the stretcher had nobody on it. >> the students on their phones tried to stay calm, but it wasn't easy. afterall, a college residence is supposed to be safe, but now there might be a killer on the loose. >> we were really afraid and i mean, the police officers were like, you're okay, we're here, you're safe. but we were really scared. >> hailey went over and over the events of that night in her mind and she remembered something about 1:15 a.m. as she was trying to go to sleep, an unusual sound. was it related? >> it was like a little thud, thud, and then it was like, maybe a pause and then there was more and another break. and some of them were louder than others. >> now, as the activity in the hallway intensified, hailey heard a line straight out of a cop show. >> the police officer said, this is now a crime scene, nobody touch anything. >> so at that time, i knew we had to do our jobs and preserve everything, you know, for the safety of the rest of the campus. >> the officers had a million questions. number one, who was the girl laying with her face to the floor? alex kogut, the girl they asked to check on had blond hair. the girl on the floor was a brunette. was she alex's roommate? it was hard to know. her face was bloody, unrecognizable. >> so then you must be wondering, well where's alex? >> right. >> the cops learned that alex had entered the dorm with her boyfriend after midnight. and then they made a startling discovery. when they looked closer at the photos in the room, they saw a young man they recognized. in fact, they issued him a ticket that very night. >> so we knew who we wanted to look for at that time. >> it was clayton whitmore, alex's boyfriend. they needed to find him and fast. he might lead them to alex. >> if we have someone that did this violent act here in this specific room, you know, what is he capable of doing when he leaves here? >> coming up, a missing boyfriend. an anxious best friend. >> and a mystifying murder. >> there were so many things that didn't make sense in the room that it was very hard to say, okay, this is what happened. case closed. >> when dateline continues. business. it's not a nine-to-five proposition. it's all day and into the night. it's all the things that keep this world turning. the go-tos that keep us going. the places we cheer. and check in. they all choose the advanced network solutions and round the clock partnership from comcast business. see why comcast business powers more small businesses than anyone else. get started for $49.99 a month plus ask how to get up to an $800 prepaid card. don't wait- call today. the campus cops investigating the murder in mcclain hall weren't sure who the victim was. they recognized a young man in photos in the dorm room. they had seen that same young man when they were patrolling the campus earlier that night. >> i observed the couple coming down the street here, on utica street. he had an open container in his hand. as he kept coming, we intercepted him right here on the sidewalk. i requested his id. i could see it was an open beer can and explained to him, we have a local ordinance here that says you cannot have an open container. >> did he seem angry? >> no, he was very cooperative. i gave him the ticket, and they started to walk away right down the sidewalk. >> the young man who got the ticket was clayton whittemore. returning home from a party with his girlfriend, alex kogut. >> when they left, did they seem fine? >> they seemed normal to me. >> small talk with the female he was with, and was able to make her laugh a little bit. so if anything, it was bothering her, she didn't let us know. >> just a normal couple out on a friday night. wasn't quite the last of him. >> no. as they both started walking away, i observed him drop the beer can. he dropped it right on to the ground. i made a comment to him, that could be another $100 fine. and he went back and picked it up. after doing that, i saw him cross the street here and the same time, the female stayed on this side of the street, and then they both continued to walk on separate sides of the street. >> alex and clayton had been dating for a year and a half by then. they were both from the town of new hartford in central new york. they got together when alex was in high school. clayton had already graduated. now, they were trying to make a go of a long distance relationship. >> they really wanted to make it work and stuff. i think it was working. i think she really did love him. >> what kind of things did she say to you about clay? describing him or the time they spent together? >> it was kind of just little things here and there, like oh, i can't wait to see him. i miss him. you could see it in her eyes that she really did want to be with him. >> clayton, number 21, had been a standout hockey player in high school. after he graduated in the spring of 2010, he spent a season playing for a college prep team in florida, living with a host family there. >> he was like the star player. he was the guy that scored the goals. >> hunter fernandez, one of clayton's teammates lived with the same host family. >> paint a picture of clayton for us. >> he was hard working, he was a really nice guy. he was funny. always had a good time. >> did you ever get into trouble? >> no, we never really got in trouble. we were always busy. >> what about girls? did you hang out with girls? >> nope. >> partying? drinking? >> he drank once. >> this sounds like the tamest bunch of hockey players i think i ever heard of. >> it was hardly surprising that alex was drawn to another athlete. and clayton was a catch. paige whitney, alex's swim team pal knew that. she had gone to high school with clayton, sat beside him in senior year math class. >> she felt like he de served a lot more and she was very, very lucky. >> so she considered herself lucky that he had chosen her? >> absolutely. >> watching them together, did it seem he really cared about her? that he really looked her? >> absolutely. you see them laughing together. you see them, you know, getting along so well. >> her family liked him, too. they had given him a care package for her and her mom had contributed $20 towards gas for the trip. once alex's swim team meeting ended that day, the couple met up, had some alone time in her dorm room, then went to dinner. alex and samantha were texting, of course. >> i asked how she was doing, what she was doing. she said, we're out to dinner right now. then they went out to a friend's house, and came back to the dorm. >> on the way back, clayton got that ticket. and the cops saw the two walk away separately. then, at 12:13 a.m., alex posted a cryptic tweet, should've known, it read, should've known. >> what do you think it meant? >> it probably does have something to do with clayton, but i don't exactly know. >> minutes later, alex swiped her card to enter her dorm with clayton. it was 12:17 on saturday morning. so now, investigators were desperate to find out where clayton whittemore was, and whether alex was with him. >> luckily, we had all his information from the ticket. >> clayton had been a model of cooperation. what could he tell them, if anything, about what had happened in the dorm room that night? >> what's your gut telling you happened? >> i couldn't put together what happened because it was so violent. there were so many things that didn't make sense in the room that it was very hard to say okay, this is what happened, you know, case closed. >> what were the scenarios that you were thinking of? >> maybe there was an altercation between roommates. maybe possibly alex and clayton were on the run and this was the roommate on the ground. maybe alex was abducted by clayton. maybe clayton had hurt the roommate. >> a lot of things were running through your mind. >> yes. >> lots of things on other people's minds, too. at her parent's house, samantha turner, alex's best buddy was phoning her friends. a college official got on the line and told her there was a situation. >> and then i broke down and i grabbed my sister and i was like, we need to go to brockport right now. at 4:00 in the morning. got here, saw the police cars. >> you didn't know at this point what had happened? >> i didn't know exactly who it was. >> hundreds of miles away, a frantic mother waited desperate for answers. but when those answers came, they would be unbearable. and they were coming soon, from the killer himself. coming up, two frantic phone calls from a mother. >> he said she was breathing and then she stopped. >> and, a son. >> what's going on there, bud? >> i did something. >> when dateline continues. new sensodyne clinical white provides 2 shades whiter teeth and 24/7 sensitivity protection. i think it's a great product. it's going to help a lot of patients. want more from your vitamins? get more with nature's bounty. from the first ever triple action sleep supplement, to daily digestive support, to more wellness solutions every day. get more with nature's bounty. ugh, when is my allergy spray going to kick in? -you need astepro. -astepro? it's faster, bro. 8x faster than flonase. it's faster, bro! it's faster, bro! it's faster, bro! it's mom to you. astepro starts working in 30 minutes. astepro and go! ♪you're the one that i want!♪ nexgard® plus helps you protect your dog from fleas, ticks, heartworm disease and more... all in one delicious, monthly soft chew. use with caution in dogs with a history of seizures or neurologic disorders. nexgard® plus. the one you want for one-and-done protection. what is cirkul? cirkul is the fuel you need to take flight. cirkul is the energy that gets you to the next level. cirkul is what you hope for when life tosses lemons your way. cirkul, available at walmart and drinkcirkul.com. hi, i'm richard lui. the u.s. says there was no ukrainian involvement in the attack on a concert venue at a moscow suburb, refuting vladimir putin's earlier claims. russian authorities arrested eleven people, including four suspected gunmen. this after isis claimed responsibility. at least 133 people were killed. and the alabama clinic at the center of a legal battle that sparked fears nationwide about the future of ivf has resumed rescheduling embryo transferred. it paused procedures in the wake of a state supreme court ruling. for now, back to dateline. welcome back to dateline. i'm craig melvin. there was a murder on a college campus. a beating so brutal that the victim could not be identified. the killer on the loose, police were desperate for answers. and they were about to get some, thanks to an unexpected phone call. once again, here's andrea canning with, after midnight. >> early that saturday morning, steven peglo, a veteran homicide investigator with the monroe county sheriff's office was called to the brockport campus. the cops had a murder on their hands, a body they couldn't identify, and a killer on the loose. >> everyone thought they knew what was going on, but nobody really did. until you got there and started to put the pieces together, you didn't know. >> as he drove to the campus, investigator peglo reviewed the facts as he knew them. one young woman was dead. another was missing. >> what we had reported, a young lady that was still alive and needed help. right then, that was my priority on the way out there. >> were you thinking clayton had taken alex and had hurt her? she was still alive? or someone else may be involved in the whole thing? >> at that point, i was thinking she was just with clayton and he had hurt her. >> you are thinking, we have to find her immediately. >> yes. >> but five counties away, a drama was unfolding that would break open this case. about 3:00 a.m., an operator at the emergency center got a call from a profoundly troubled dad. >> yes. my name is scott whittemore, and my son, clayton, called and said he killed someone. >> it was a stunning statement, even for a 911 dispatcher. the dad didn't know much. >> where did this happen? >> i don't know. >> where is he right now? >> i don't know. >> the father reported that his son was in a bad way. >> he is talking about killing himself, too. i don't know what's going on. except he got in trouble. >> the divorced dad admitted he was out of the loop about family matters. now he was doing his best to stave off a tragedy. >> do you know if he has any weapons? >> i don't know. he did ask me for what i have. i have a permit for a pistol. >> he asked for your pistol? >> yes. he doesn't have it. >> did he say what he wanted to do with it? >> kill himself. >> the dispatcher asked scott to call his son back to find out more. minutes later, the father was back on the line. >> he has the girlfriend in brockport, his mom thinks he's probably on his way back from brockmore. >> they got clayton's mother on the line. >> we are trying to find your son. do you think he was out visiting his girlfriend at suny brockport? >> he is in canada right now. >> he's not in canada. >> he's not? >> no. at least his cell phone isn't in canada. if you were just talking to him on his cell phone, he's not in canada. >> okay. >> okay, just take a couple deep breaths and we're going to try to find him so we can get him some help. >> the dispatcher got the name, alex kogut from the stressed out mom. seconds later, he was on the phone to the campus cops in brockport, now finally the pieces of the story began fitting together. >> we got a call from a father, about an hour ago, that said his son called him and stated that he killed somebody. the son's name is clayton whittemore. he is out there with a girlfriend that has an alex kogut at college. >> you're looking for him as well? >> we had him earlier on an open container at midnight. >> is the girl okay? >> well, we don't know where this alex kogut is. we can't locate her, but her roommate is doa. >> that's the theory the campus cops were acting on. that the roommate was dead and alex was with clayton somewhere. but then, new information from clayton's mom. clayton had just called his sister and told her a frightening story about alex. >> and he said something like, she was breathing, and then she stopped. >> he said the girlfriend stopped breathing? >> yeah. >> clayton's mother was beside herself. >> did you get ahold of the college out there? >> yeah, they're looking for him. we don't know what the heck is going on. everyone is out looking to see if they can find him and make sure they are okay. >> and then once more that morning, the call line lit up at the 911-center. this time it was the call everyone was waiting for. clayton whittemore was on the line. >> what's going on there, bud? >> um, i just, i did something. >> it was 3:44 a.m. the horror of what had happened in room 108 would soon be revealed. >> coming up, who had clayton whittemore killeed? >> i didn't know who, i didn't know anything. i just knew she was gone. >> when dateline continues. i didn't know it then, but it can progress to ga, an advanced form of the disease. his struggle with vision loss from amd made me want to help you see warning signs of ga, like: hazy or blurred vision, so it's hard to see fine details, colors that appear dull or washed out, or trouble with low light that makes driving at night a real challenge. if you think you have ga, don't wait. treatments are available. ask a retina specialist about fda-approved treatments for ga and go to gawontwait.com [♪♪] looking for a moisturizer that does more than just moisturize? try olay regenerist for 10 benefits in every jar. olay visibly firms, lifts, and smooths wrinkles, by penetrating the skin, to boost regeneration at the surface cellular level. try olay. ♪you're the one that i want!♪ nexgard® plus helps you protect your dog from fleas, ticks, heartworm disease and more... all in one delicious, monthly soft chew. use with caution in dogs with a history of seizures or neurologic disorders. nexgard® plus. the one you want for one-and-done protection. 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(vo) ding dong! homes.com [coughing] copd hasn't been pretty. it's tough to breathe and tough to keep wondering if this is as good as it gets. but trelegy has shown me that there's still beauty and breath to be had. because with three medicines in one inhaler, trelegy keeps my airways open and prevents future flare-ups. and with one dose a day, trelegy improves lung function so i can breathe more freely all day and night. 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. ♪ what a wonderful world ♪ ask your doctor about once-daily trelegy for copd because breathing should be beautiful. clayton whittemore was at a rest stop when he called 911 with a stunning admission. >> i'm turning myself in. >> um, i just did something. i can't take back. and just got to turn myself in. >> it was almost 4:00 a.m. a frantic hunt that had pulled in multiple police agencies, emergency dispatchers, college officials, and two sets of anguished parents was almost over. >> there were two officers, two new york state troopers who, you know, were patrolling the throughway that night. >> sandra is the district attorney of monroe county in western new york. >> they were called to respond to the service area, not knowing what to expect. at that point, it was one dead on the brockport college campus and perhaps another missing. >> and clayton was there waiting? >> he was. he walked over and said, i'm turning myself in. they noticed bloody sneakers and they noticed blood on his hands. >> within seconds, 21-year-old clayton whittemore was cuffed and in custody. now for his car. what could it tell them? >> they wanted to check the trunk. they didn't know if there was a body in the trunk, because at that point, they still hadn't determined, you know, who it was actually on the dorm room floor of room 108. >> that was about to change. the cops in brockport, who initially thought the victim was alex's roommate had learned the roommate was staying elsewhere that night, but where? they started an urgent search until they spoke to her, they couldn't be certain of the victim's identity, because of the hair color. investigator steven peglo. >> the girl laying on the floor had dark colored hair. when you saw the photos that alex put up in her dorm room of her and clayton, she had much lighter hair. the roommate had darker hair. >> investigators knocked on student's doors questioning them. then, a nugget buried in a conversation. alex recently dyed her hair brown. they had what they needed to id their victim. now they wanted to hear from one more person, alex's roommate. when she did call in, she had been staying in another dorm room. >> we had her come to us, and we were positive. >> positive that the girl on the dorm room floor was alex kogut. lovely alex. only 18 years old. samantha turner, who rushed back to college early that morning was devastated. >> i just broke down and i knew at that point, my life was changed. >> you just knew what had happened without anyone telling you. >> uh-huh. i didn't know how, i didn't know who. i didn't know anything. i just know she was gone, and i could never see her again. >> sandra whitney and her daughter, paige, are family friends of the kogut's. paige, remember, was a student at brockport, too. her roommate woke her up around 7:00 that morning. >> she said, we have to go, we're all meeting together. something happened. paige called me and she said something happened to alex. i said, alex? what? said, it was a terrible accident. and she said -- >> i said, well is she okay? >> she said no. i said, is she in the hospital? she said no, mom, she's not. and i said, has she died? and she said yes. so, i was shocked and all i could think was, what could have happened to alex in her dorm room? >> the new york state police were asking clayton whittemore that very same question. that very morning. >> i mean, your relationship? >> no, we were good. >> clayton put the pieces together for the police about what happened that night. and it began with the fact his relationship with alex wasn't so good afterall. the couple had dinner, then the party. clayton said he and alex drank moderately. at the party, he got annoyed with her, said he felt disrespected. >> but if anybody else said anything to her -- >> as they walked back from the party, clayton got the open container ticket. >> so, i was already aggravated and got aggravated more. >> clayton walked to the other side of the street to cool off. and then alex posted that final cryptic tweet. should have known. >> we'll never really know what that meant. >> what do you think it meant? >> maybe we should break up. >> at 12:17 a.m., alex swiped into her dorm. she and clayton entered her room. clayton said they were fighting about cheating. old stuff, he called it. >> what was she saying? >> she is like, i saw a picture on your phone way back, you know, in november of last year or something. >> yeah. >> a picture of my sister, for god's sake. >> then, he told the cops she got physical. >> started pushing me and pushing me and pushing me. she kept doing it. and was she saying anything when she was pushing you? >> the investigator pointed out, clayton was a strong guy. alex was tiny. >> you didn't feel threatened by alex, it was more than that, right? >> i don't even know what it was. i don't know. i don't know how to explain it. i don't know if it was my temper, or her hitting me in general. like pushing me and stuff. >> but you're not hurt? >> no. >> right? >> no. >> he told the cops he asked her to stop, but he said she wouldn't. and when he offered to leave, he said she told him to stay. and then this. >> all of a sudden, i just snapped. i hit her back. >> where did you hit her back? >> i threw her against the wall. >> the attack that followed was savage, unthinkable, in a tiny dorm room surrounded by sleeping students. clayton whittemore beat his girlfriend to death. investigator has seen plenty of homicide scenes, but never one like this. >> it was a few of us in the room. people were like, i have blood on this. i have blood on this, and give you an idea on the rage that had gone on in that room. >> peglo, who studied the interview video, says there's one thing he can't forget. clayton told police near the end, he realized alex's breathing had become labored. the girl he said he loved was dying. >> you know, it was like watching an animal die, you know? that's why i did the other stuff that i did, because you know, someone you love. >> yup, okay. >> so, you see her suffering and you think she's going to die, is that right? >> yeah. i didn't even think. getting help. >> didn't get help. didn't call an ambulance. didn't occur to him. instead, he hit her until she died. to put her out of her misery, he said. >> must have seemed almost impossible. how could she be murdered? >> exactly. disbelief, shock. it's not real. it's not real. that doesn't happen. you don't go away to college and suffer that. you just don't. >> clayton whittemore was charged with second-degree murder. he pleaded not guilty, because clayton whittemore had an explanation and his attorneys would reveal it at trial. >> coming up. could anything explain such violence? >> you said you saw a lot of it, huh? >> i saw it all. >> the verdict, when dateline continues. ember card to use for your plan benefits. get credit every month to pay for healthy food... -hmm! utilities... and more over-the-counter items at no extra cost to you with unitedhealthcare. after advil: let's dive in! but...what about your back? it's fineeeeeeee! 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[♪♪] if you're only using facial moisturizer in the morning, acetaminophen blocks pain signals. did you know, the best time for skin renewal is at night? olay retinol24 renews millions of surface skin cells while you sleep. wake up to smoother, younger-looking skin with olay retinol24. ugh, when is my allergy spray going to kick in? -you need astepro. -astepro? it's faster, bro. 8x faster than flonase. it's faster, bro! it's faster, bro! it's faster, bro! it's mom to you. astepro starts working in 30 minutes. astepro and go! it wasn't until the spring of 2014, almost two years after alex kogut died, that clayton whittemore went on trial. although he told the cops he had beaten his girlfriend to death, he entered a plea of not guilty for second-degree murder. the gruesome images in room 108, the mountain of incriminating evidence, even his words. >> i didn't even think of getting help. >> he was a ticking timebomb, a killer years in the making. >> how does this young man go from star athlete, popular, college student, to what some would call a monster? >> you know, our theory that night was his anger was just building, building, and perhaps fueled by alcohol. >> prosecutors tried to show that clayton whittemore established a pattern of violence. they called exgirlfriend, melinda, to testify about one scary episode. >> when we were fighting in a parking lot, he had choked me. he tried to hold on for a few seconds. i thought he might not stop. eventually he did. i locked him out of his car to cool down, and he did. i blew over it. >> that one was serious? >> yeah, it was scary. >> hunter fernandez was also called to the stand. hunter played hockey on that college prep team in florida with clayton. hunter, too, had a scary experience. it happened after clayton drank a half dozen beers. the one time, hunter says, that he saw his teammate drink. >> he walks in the kitchen, and grabs a knife, and he raised it above his head. it looked like he was possessed. he took a step towards us, and our host mom sees what's happening and she says, put the knife down. >> clayton killed alex kogut, didn't even try. they didn't dispute his anger was years in the making. they argued this wasn't a case of murder. their client was guilty of the lesser charge of manslaughter. why? they said he was under the influence of extreme emotional disturbance when he killed alex kogut, because clayton whittemore was a victim himself. >> i'm turning myself in for what i did. >> okay. >> the man who called you is the man who should turn himself in. >> that's clayton talking to the 911 dispatcher hours after the murder. he is talking about his dad. telling the dispatcher his father had abused him and his family for years. >> happened my entire life. >> you saw a lot of it, huh? >> i saw it all. watched my brother get beat with a baseball bat by my own father. i watched my own father break my sister's nose. throw my own mother down to the ground. and beat her. i watched him try to shove a remote control down the throat of all his children. >> the cops in the interview room asked how he felt about his dad now. >> you and your dad have a relationship now? >> not really. not like people i'm really close to. growing up with my dad. one man i december prized. >> despized. >> clayton wrote an apology. sorry to the family and you, he texted. nothing will ever fix or undo what i did. i became my father. in court, clayton's sister took the stand and supported her brother's story. their father, scott whittemore, did not respond to dateline's calls. there's no record of complaints against him, but a defense expert, a psychiatrist, testified scott admitted that as a former marine, he may have been rough. because of that abuse, the expert concluded that clayton was suffering that extreme emotional disturbance and snapped in the dorm room. the prosecution begged to differ. >> it's just sad and tragic. you know, we never discounted or denied his past, but that doesn't excuse what he did. >> three weeks after the trial began, the case went to the jury. the verdict was swift, guilty of second-degree murder. >> i just felt this overwelming sense of relief that the truth came out and that there was finally a verdict. it was the right verdict. >> alex's mom did not attend the trial, but followed it closely and tweeted. >> becky kogut, after the verdict tweeted, justice for my beautiful baby. did you talk to her about the verdict? >> uh-huh. >> what did she say? >> it was a private conversation between two moms. there were tears. of course. doesn't bring back alex. it doesn't. >> clayton whittemore was sentenced to 25 years to life. among those who knew the story of alex kogut's life and death, there was awareness of the challenges of young love. especially because there was evidence that showed clayton had a history of threatening alex. he left angry voice mails on her phone. district attorney. >> there were almost 30 voice mails that she saved from him. they were all of the aggressive, controlling nature. we argue to the court to seek admissibility of them at trial. >> the voice mails were not admitted in court, but prosecutors read an excerpt for dateline, editing out the expletives. >> i'll kill you next time i see you, don't call me, i'm sick. i'm sick of you. i left a lot of words out. >> when you add in those expletives, it is really hard to hear. >> it was. these were voice mails that really were scary. >> those close to alex and her family said they never knew about the voicemails. never knew there was a problem. they said there were no red flags about clayton whittemore. >> that's why it's out of the blue. never saw that coming. >> nothing. totally, totally caught me off guard. >> perhaps for parents, there is a lesson to be learned. ask questions, know what's happening. even if there are no warning signs. >> even if, you know, they might be not wanting to talk about it, you know, ask those questions. >> after alex died, sandra whitney and her family started the purple pinkie foundation. purple symbolizes the fight against domestic violence. it was also alex kogut's favorite color. sandra came up with the idea as she comforted alex's former teammates. >> i said, so paint your pinkies purple. this is for alex. you have more strength in your little finger than the worse thing that can come at you. >> two years later, there were still purple ribbons in alex kogut's hometown. still friends attending a college memorial, at a college that as itself had to heal. a college that has since opened a center to raise awareness about dating violence. and there are still those like paige whitney, who will never let the memory of a graceful, joyous, young spirit fade away. >> for the rest of my life, whenever i see purple, i will think of her. whenever i hear a story of any type of domestic violence, i will think of her. and i will not stop telling her story. >> that's all for this edition of "dateline." i'm craig melvin. thank you for watching. couldn't comprehendallo: i what was happening. i couldn't sleep. losing my husband, it's an image that >> i couldn't comprehend what was happening. i cannot see losing my husband. it is an image that will never