>> they were rocking back and forth, traumatized, disturbed. >> what had the girls seen that day? could they provide a clue to help crack this case? >> the twins said nikki had a second boyfriend. >> two boyfriends? >> two boyfriends. >> jealousy, passion, revenge. >> she was fearful. she contacted the police. >> what's secrets might the twins reveal? >> terrifying. is it possible that this could happen? >> i was shaking, oh my gosh, oh my gosh. >> ♪ ♪ ♪ >> hello, and welcome to dateline. nikki whitehead was a single mom working towards a brighter future. but that dream died when nikki was viciously murdered. her death left her teenage girls seemingly inconsolable, and investigators were committed to solving her murder. the answer would prove elusive. in the end, difficult for even the veteran detectives to believe. here is keith morrison with bad blood. >> once in a while, in a complicated life, a woman can get lucky. which is why you are looking at the sweet little town called conyers, georgia. and deep downtown, with gated communities, good schools, it was pure luck that brought nikki whitehead to this house, in this quiet, safe neighborhood. just far enough away from atlanta, that capital of overheated ambition down the drive. here in conyers, she could give her beautiful twin daughters a better life than hers. but of course, luck, fortune and fate can go either way. sometimes, in ways very hard to comprehend. >> everything about this goes against nature. >> how can somebody do that? >> it was definitely the bloodiest crime scene i had ever been to. >> in the next few minutes you will know exactly when it happened, where it happened, how it happened. but of course, the real question is why it happened. and the answer to that, as you will see, is kind of complicated. that is how nikki whitehead's life was. >> i love everything about her. >> debra harris grew up with nikki, she was a wild child, pretty, fun and irresistible. >> nikki, to me, she was a phenomenal, amazing person. >> she says she was effervescent, said nikki's mother, linda. bigger than life. >> she was the kind of person, when she comes in a room, she just takes over the space, you know, with her personality, her laughter. >> but when nikki was 12, she was a handful. linda was a single mom with kids at the time, so she agreed to have her move in with her grandmother. but she let the girl run wild. boys, parties. >> we grew up kind of fast. and later, she became pregnant at the age of 18, or 19. so we moved kind of fast. >> pregnant with identical twins, who she named jasmiyah and tasmiyah, jazz and tazz, born in 1993. the twin's dad was around briefly, then gone. and their mother figure, nikki's grandmother, della. nikki's mother linda did not like that. >> i wanted nikki to get her own place, establish her own life, and my mom would discourage that. you know, she would find ways to tell her no, you are better off here. >> that is how it went four years. but nikki had learned how to style hair, and was doing well at it. and the possibility of independence. >> she eventually wanted to get out of the control of della, right? >> she wanted to, as the girls got older, she definitely wanted to take control of her life. >> then one day, in 2000, nikki was shopping at the mall. and robert head just happened to be in exactly the right spot. >> i was sitting on the fountain one afternoon at about 6:00. and they're walks in nikki, coming into the mall. >> and your eye caught her? >> yes, i just could not let her get away, she was outstanding. >> that he was old enough to be her father did not matter, robert was in love. so we persuaded her to go to dinner that very night, took her dancing. he bought her nice things, treated her like a lady. >> she was my movie star, that's what i called, or my movie star. >> this movie star with two sweet daughters. he also soon love them as if they were his own. and that is how nikki came here, to safe, secure conyers. this is robert's house, and here they made a family. unusual in some ways as it appeared, but -- >> it was nice, really nice. everything clicked just right. >> and she wanted her life to be even better, so while she kept her job as a hairstylist, she enrolled in atlanta's bauder college, to study fashion design. >> that's what i really learned that she was a hairstylist. >> rhonda taught a couple of her classes, she thought nikki had a sense of purpose. whether it was about her kids, passion for other people's hair -- >> i came into the class early one day, as i normally do, look appearance at, miss anderson, what is going on with your hair? [laughs] i said what? excuse me? and then she asked me this question, do you have a hairstylist, does she know that you have your hair looking like that today? >> i said yes, and no. she said, miss anderson, i am giving her one more chance. one more chance, and if it is not right, i am taking over. >> rhonda loved nikki, and nikki loved her girls. she put the twins in dance, music classes, and at school they won awards. >> their teachers described them as almost angelic, sweet, happy and engaged. and there are pictures of them, one on each of nicky's arms. >> catie beck, a reporter at an nbc affiliate in -- >> he just described to that, way she had a sweet demeanor in their classrooms, and with their classmates. they were almost timid. then, as they reached their teens, they changed, somehow. and in the ways children often do, in the way that nikki herself one did. and just like nikki, the twins were sent to live for a couple of years with a rather permissive family matriarch, della. until 2010, when nikki welcomed tasmiyah and jasmiyah back. all together again at robert's house. a fresh start and nikki turned up at school beaming. >> yes, she was in a very good move. she looked great, a new look in her, she had braids in and she was happy. >> as if the braids in her hair or a kind of announcement. her girls were back. >> they were pretty much her pride and joy. >> oh, you started to think about her? >> it's hard, it is really hard. >> january 13th, 2010. a sheriff's deputy happened to be in the neighborhood, the girls had just come home from school. the deputy saw the look of horror on their faces, heard their screams as they came pounding on his car. >> one of the twins ran up, and really beat on the side of the car and told them, they had come home from school to find their mother murdered. >> coming up, two distraught daughters are about to reveal a clue. >> we are told by the twins that nikki and a second boyfriend -- >> -- to boyfriends? >> two boyfriends. >> when dateline continues. join the millions already taking ozempic®. ask your health care provider about the ozempic® tri-zone. ♪ it's the most wonderful time of the year ♪ ♪ non-drowsy claritin knocks out symptoms from over 200 allergens. without knocking you out. feel the clarity and make today the most wonderful time of the year. live claritin clear. ♪ chevy silverado has what it takes to do it all. with up to 13 camera views. and the z71 off-road package. ♪ you ok? 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>> trying to get out. and then along this will, you can see a bloody imprint of here breeds. nikki had her here in breeds where she fell, split down the wall. with the most severe blood came when she was face down in this area. it's clearly where the assailant got on top of her from behind and started stabbing her at the base of her neck. >> this huge amount of blood? >> yes, this was the largest pool of blood in this area right here. >> she was dead, ordinary dead, when her assailant dragged her to the bathroom. that's where she was in the tub of water when her daughter saw her. before they ran to the street screaming. >> as we get there, you have these two beautiful, young 16 -year-old girl's, that saw their mother murdered. >> conyers police captain jackie dunn wanted to get jas and tas away from the house. and that's when he noticed they were hurting themselves. >> one of them was biting their arm. and we were like why are you biting your arm? she said i'm so upset, and i do that when i'm upset. >> this was the worst kind of case. detective needed information fast. but how do you get it from children who have just left their dead mother? >> i hurt. >> they were going in and out of fits of tears, crying. >> i want my grandma. >> asking for their mom. >> i want my mama. >> they both seem to be walking back and forth. contemplative, traumatize, disturbed. >> it will be okay. i want grandma. >> it will be okay. >> i can remember thinking, man, i hope there is a family member to adopt these girls. because they really need somebody to reach out and the good parents for them. >> word spread through the late afternoon gloom. a friend called harris. >> she had asked me when was a lost time i talk to nikki i said i talked to nikki saturday. she told me you may want to go over to her house because she said the helicopters were there. and the news reporters. >> tell me, when you heard that, what did you think? >> i don't know, it is like tunnel vision. i guess it was slow motion. you could call nicky's mother linda and told her something bad was going on over at nicki 's. >> i was so nervous i don't know what to do. i was like, oh my gosh! oh my gosh? i was just shaking. i could hardly drive. >> linda pulled into her daughters neighborhood and saw a police officer. >> he said ma'am, could you pull over there? i said no, i need to go to my daughter's house. he said ma'am, will you just pull over their pleas? >> i pulled to the side and i said what is going on? he said man the only thing i can tell you is that your daughter has expired. >> there is no getting over news like that. as nikki's try to take it in, investigator set to work trying to figure out who did this. the girl said their mother was still in a room with the door locked when they left the house for school at 7:30. >> we missed the bus, so we had to walk. >> perhaps the crime scene revealed more clues than the girls could. lieutenant chris moon headed back there. >> looking for cellphones, computers. typically victims are gonna have called are spoken with their assailants just before the murder around the time of the murder. >> the attack did not look random. it was not met -- but it was so violent. >> that suggested rage. and when you look at a rage murder, it's usually somebody very, very close to the deceased. >> so naturally, the first person they wanted to talk to was the man of the house, robert head, nikki's boyfriend. but robert was in around. >> well is the last time you saw robert? >> yesterday. he left, he came in on sunday. he stayed for a day. he left. >> here's the thing, robert was a long haul truck driver, which explained his absence. but not where he was. especially when nikki was murdered. >> we had to find robert and we had to check on his gps. >> that takes a while, right? >> yes sir. >> meanwhile, detective spread out through the neighborhood. knocking on doors. did anyone see anything unusual? >> a couple a neighbors said they saw a red car in nicky's driveway that afternoon. a car they had never seen before. and a black car as well. they asked the girls. who could've been there? >> does your mom have any other friends or anybody else that come over? >> she talks a lot of men. but the only one i've been hearing her talk to lately is joe. >> joe? who was joe? >> we are also told by the twins that nikki had a second boyfriend, joel carter. >> two? boyfriends >> two boyfriends. >> now that got the investigators attention. time to dig a little deeper into the life of nikki whitehead. >> coming up. >> jealousy or by blood involved? >> there clearly have an argument, the elegant streaming over the phone. he was in the media person of interest. >> when dateline continues. the time. ♪ ♪ today's a good day. ♪ ♪ i screened with cologuard and did it my way! ♪ cologuard is a one-of-a kind way to screen for colon cancer that's effective and non-invasive. it's for people 45 plus at average risk, not high risk. false positive and negative results may occur. ask your provider for cologuard. ♪ i did it my way! ♪ (josh allen) is this your plan to watch the game today? 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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. detectives in conyers, georgia only on verizon. were getting a crash course in the short life of nikki whitehead, found stabbed to dead in the home with her live in boyfriend, robert, and with her teenage daughters, jazz, and tazz, who had each other for support. >> the girls put their arms around each other, and they said it will be okay, we will find out who did this. they were clearly relying on each other to get through this. >> but, they were able to convey some real information. >> any idea who she was talking to? >> it was joe. >> who is joe? >> her mother had a second boyfriend, a man named joe carter, a local barber, whose shop was right next to nikki's salon. a love triangle? veteran homicide detectives said it sounded like a recipe for murder. first, they talk to robert, boyfriend number one who is on the road in his long haul truck. how did he react to the news? >> he was devastated. >> easy enough to check in on robert, gps records put in a full days drive away when nikki was murdered. and when they met him, as we did, they could plainly see that his grief was real. >> i mean, that was my better half, and she is gone. it is a hard thing. >> this was how detectives discovered the unusual nature of robert and nikki's relationship. roberts that he knew about the other boyfriend, and he said he did not mind. he said he wanted nikki to be happy when he was away on the road. >> and he is a trucker. when he was home, he expected for her and him to be a couple, and when he was away, he realized she would have other relationships. >> but what about joe? how did he feel about that? he was upset about something, says the twins. the night before the murder, they said that joe and nikki had a nasty, loud argument on the phone. >> all she told joe is that he could not come over that night. >> or they suggesting that they might have been jealousy, bad blood involve? >> that is what we initially thought. obviously, he was an immediate person of interest. >> though he was, remember, the neighbors spotted a black car near nikki's house the day she was killed. joe's car, perhaps? >> do you know what joe drives? >> no, i know the black car in the driveway. and it is a black -- a black car. >> richard reid was the rockdale county district attorney. >> we need to look at joe carter, especially since nikki and joe had been in an argument. they were breaking up, and that is a dangerous time in a relationship. it can be a dangerous time in a relationship. >> it was not hard to track joe down. he was in the barbershop where he worked. >> it was around closing time, ready to pack up and get out of their. and they approached me and my friends, and they basically said that she has passed away, she is dead. i mean, i was shocked, i was in shock. >> how did he react when he came to see? >> he started to weep. >> did he claim not to know? >> he claimed not to. >> but reactions do not always tell the real story. >> they were basically asking about me, our relationship, when the last time was that i saw her. i started to realize that i was a suspect. >> the detective did what any good detective would do. he looked for the sort of marks that nikki might have left on the assailants body. >> look at his hands, arms, knees. he took off his shirt -- >> but joe was clean, not a suspicious scratch on him. detectives learned that car outside of nicky's house did not belong to him. still, they brought him in for questioning, hooked him up to a polygraph and asked him point blank if he killed nikki. and the polygrapher determined that he was not deceptive in answering questions. >> i want to find the killer, i want them to know that it was not me. >> so that was it for joe? >> it appeared that joe was not involved in the death of nikki whitehead. so, two boyfriends and two dead ends. >> you know, in addition to robert head and carter, could it have been a stranger? did you look into that? >> we did. >> they still wanted to know who owned another car, a red one that was also seen in nikki 's driveway the day of the killing. it did not take long to find out, it belonged not to a murderer at all, but a friend. >> nikki had missed a hair appointment with this friend, the friend had come by, knocked on the door and had not been able to make contact with nikki, and left. >> imagine had she opened that door, such a grizzly scene, so full of rage and passion. so, who killed nikki? somebody close? then, as they struggle to figure it out, investigators encountered, in their own police files something rather stunning. >> coming up, family secrets -- there were a few yet to be revealed. >> it turned into a fight. >> a physical fight? >> a physical fight, and she contacted police. >> when dateline continues. on top of the worlddddd!!! before advil. advil targets pain at the source of inflammation. when pain comes for you, come back fast with advil liqui-gels. 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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. >> i'm katie phang with the only on verizon. hours top stories. in jacksonville, florida, authorities say three people were killed in a racially motivated shooting saturday before the gunman killed himself. the victims identities have not been publicly released. the fbi is investigating it as a hate crime. fifa has suspended president of this banner soccer federation, louise riebe alley,'s for football related activities for 90 days. he was captured on live tv kissing player jennifer mozone after a world cup win. and she said she did not consent to the case. now, back to dateline. >> welcome back to dateline. i'm craig melvin. miss nikki whitehead for that fiercely during the attack that ended her life. the blood, trailing from her dining room to the bathroom, revealed just how savage it was. but with little evidence pointing to a killer, the investigation seemed to stall. until that is, a secret emerged from nikki's past. once again, here's keith morris with bad blood. >> the investigation into the murder of nikki whitehead was not offering up any usual suspects. the two men in her life, robert head and joe carter had been eliminated. and a home invasion seem very unlikely in her gated community. >> there was no histories of any peeping tom's. no histories of any unsolved in the neighborhood. so we just kept coming to dead ends. >> the thing is, they felt sure this had to be a rage murder. so violent, so protracted. which made it very likely it was someone nikki new. even possibly, a family member. >> we started getting into some of the family dynamics. >> that's when they've turned up in police files, this remarkable incident back in 2007. one brief snippet of family history, but an event that changed everything that came to after. >> conyers 9-1-1, yes ma'am i just woke up and my daughter is gone at the house. >> that was the voice of nikki whitehead. >> meaning your daughter was abducted? >> i don't know, man. i woke up the door was unlocked, and she's gone. i have twin girls. one of them is gone. >> how old is your daughter? >> oh lord, 13. >> you can hear her terror. >> oh lord, my worst nightmare. >> do you think maybe somebody came and got her? >> i don't know if somebody came and got her, ma'am. she doesn't do stuff like this. i don't know. >> a few hours later, nikki learned that her daughters did do stuff like that. jas had not been kidnapped. she snuck out to fool around with a boy. >> up until that day, i believe in nikki's mind she had perfect girls. nikki realize that they were necessarily the girl that she thought they were. >> nikki was determined to help her girls avoid the mistake she made at their age. so, she crackdown. a curfew on boys, cell phone use. the following months would be familiar to many parents of teenagers. screaming, slammed doors, stony silences. >> and then one summer night in 2008, a year after jas sneaks out of the house. >> a big argument and it turned into a fight. >> a physical fight? >> a physical fight. it was tas and jas against their mother. at the time, i think she felt fearful and she contacted the police. >> was it the right decision to call the police? that ensured the family ended up in juvenile court. nikki asking the judge to help her teach her daughters a lesson. instead, the judge was blaming nikki. >> i guess the judge thought they were too cute and too smart. that no, they couldn't be doing you -- know. he did not take it serious. >> what did he decide to do? >> well, he asked my daughter -- he said, do you want your kids to come back home? as she said, no, your honor. not unless they understand i'm not going to tolerate that kind of behavior. as so, he was like, you mean to tell me you don't want your kids to come home? >> what nikki wanted was a court sanctioned demand that her daughter's obey the rules. erica but that is not what she got. instead, the juvenile court judge sent the girls to live with della, their great grandmother. >> what they were doing what were they doing while they were in dallas house? >> pretty much whatever they want. they kind of when wild. and got >> in trouble repeatedly. in school and out shoplifting, smoking marijuana, seeing the wrong type of boys. >> well, she didn't want that. she knew she was going back to when she was their age and in her grandmother's custody. she didn't want that for her kids. >> it seemed that della was undermining her. and had somehow stolen away the daughters who matter to her more than anything else in her life. >> she really wanted them back. really wanted them back. >> how did you know this? how did she express this? >> she said every day. i want my girls. i'm gonna fight for my girls. >> and in january 2010, nikki finally won. the judge ordered the girls back to nicky's. and jas and tas, did not like it. not one bit. >> so they start screaming and hollering, i don't want to go back with her! why would you make us go back? >> in court they were doing this? >> yes. >> nikki told her mother not to worry. >> she said i'll be fine. phil come around. >> a few days after the court's decision, on a saturday night, foot nikki on a welcome home party for the girls. >> they hugged me. they kissed me. >> and that was the last time yucca saw nikki. four nights later there they were, jazz and tas answering the increasingly pointed questions of a couple detectives. >> can you tell me what happened when you go on that day? >> it seems the girls were still wearing outdoor gloves. the detective asked could you take them off please? >> it's just procedure since your here. let me see your arms i need to see your arms. >> when we did that, we did see a cut on one of them is hand. we saw bruising on the knuckles, skin marks. bite marks. >> bite marks? >> when we asked them to explain those -- >> the bite marks could have been self inflicted. remember the girls were so upset on the way to the station? they were biting themselves. and the other cuts and scratches? the twins told the cops they had been fighting with each other. >> you were fighting? >> yeah, we don't get along yesterday. >> it was as they told their story detective dunn took a good look at jas and tas. and a disturbing idea settled down somewhere in his brain. >> i haven't made up my mind, but i'm suspicious. >> coming up. suspicious? were there reasons to be suspicious? >> we watch the high school video surveillance ads we see the twins showing up two and a half hours after they should've for school. >> when dateline continues. before advil. advil targets pain at the source of inflammation. when pain comes for you, come back fast with advil liqui-gels. kayaking is my thing. running is awesome. but her moderate to severe eczema would make her skin so uncomfortable. now i'm staying ahead of it. dupixent helps heal your skin from within. so, they can have clearer skin and less itch. serious allergic reactions can occur that can be severe. tell your doctor about new or worsening eye problems such as eye pain or vision changes including blurred vision, joint aches and pain, or a parasitic infection. don't change or stop asthma medicines without talking to your doctor. ask your doctor about dupixent. icy hot. ice works fast. ♪♪ heat makes it last. feel the power of contrast therapy. ♪♪ so you can rise from pain. icy hot. my a1c was up here; now, it's down with rybelsus®. his a1c? 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>> i heard that. and it stunned me. >> but teenager sometimes do talk that way. it is a mean they actually would do anything about it. so the detective set about fact checking the twins version of events on the day of their mother's death. starting with their claim that they had to walk to school that morning. >> they told us that they had overslept a little bit. that they had missed the bus. and had walked to school. >> it was a rush, said the girls, but they did get to school on time. >> made all your classes today? >> yes. >> so, the cops did what the cops do. they checked surveillance tape from businesses along the route to school. and what do you know? >> law enforcement had observed the girls walking down the roadway next to the gas station, a little after 10 am that morning. >> nowhere near on time as the school surveillance cameras would confirm. >> we watch the high school video surveillance and you see the twins showing up around two and a half hours after they should have, for school. >> so, the twins were caught in ally. and it was a big one. and it was in proof of murder, they flatly denied any involvement. even when they were put in separate rooms, they presented a united, twin front. >> they wouldn't sway. there was never any disloyalty to each other. they never said any negative comment about each other. >> getting one to flip on the other was not gonna happen? >> no. >> after those interviews they release the girls to the juvenile court farm them out a family in. france and the police had their dna, photos of their injuries like those self inflicted by marks off to the labs. but and then they waited. pretty sure science would tell them that the sweet little girls were anything but. >> did they appear manipulative to you? >> absolutely. >> i'll give you for instance, jasmiyah is in one room, tasmiyah it's taken to a similar interview room. it's apparent that tasmiyah knows there is a recording system in that room. and she starts to pray. >> i really want them to catch this person. please, god. >> she knew that some points that somebody would watch that video and would see, young, innocent sweet girl. asking god to help law enforcement find the person who did this. >> meanwhile, that the glacial place these things occur, the crime lab worked on the dna. and poured over those photos of the bite marks. one on tas's arm was the impression of a big ugly bite. they compared the top contours of that by two a mold of nicky 's mouth. the similarity was uncanny. >> nikki was the most likely source. >> had their mother between them trying to fight off the attack? >> the bite mark on tas's arm, it was as if she had her mother and a chokehold from behind. and her mother, nikki, is biting her trying to get away. >> and when when detectives saw themselves biting themselves right after the murder. maybe that was an attempt to cover-up evidence. then the dna results came. back they knew they'd find nicky's blood. but remember, one of the twins had fresh cuts on her hands. and sure enough for nike's blood mixed with, her likely assailants a, match. it belonged to one of the twins. but which one? >> they're identical twins, they have identical dna, so we couldn't tell for sure which twin the blood came from. >> by this time, the twins had been out in the world, without a word from the police for five months. wsda reporter katie back. >> i think those months built their confidence. built on most an arrogance that we're going to get away with this. >> so, you can really imagine how it was, may 21st, 2010, just after school. >> how did they react when they were arrested? >> shocked. they thought it was over with. five months. >> the arrest was big news in atlanta. two sweet little girls charged with the murder of their mother. who would have thought? >> i mean, people were riveted by this story. >> oh yes they were. and when the twins finally told their version of events that unfolded on january, the city was riveted all over again. >> coming up. the fatal struggle. did their mom started all? >> i kept telling her to stop. just stop. >> when dateline continues. that starts working in 30 minutes, while other allergy sprays take hours. with astepro's unbeatably fast allergy relief you can astepro and go! 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in fact, said the twins, it wasn't their fault. she started it. >> she started cursing and stuff. i think she was mad about us being late. >> that morning they said, nikki was furious they were late for school and picked up a pot in the kitchen, they said, and swung at them. >> she still calling us horse and slots and everything like that. and stupid and everything like that. and she threatened us. like, you know, we all gonna die today. >> that's jas. then tas picked up the story. >> so, you took the pot away from your mom. what happened then? >> she kind of charged forward. not at me though, at jas. >> now nikki had a knife, said the. girls tumbled room to room trying to get away from her before she cut one of them. and in fact, said tas, that's how her finger got hurt. >> i kept telling her to stop. just stop, just stop, just stop. >> but she didn't. they said this. >> so i'm trying to punch. or i guess. i think it tas stabbed her. she stabbed her. >> at this point in time, how many times did tas stab her? >> at some point, exhausted, the twins said they all called a truce. it didn't last long. >> they both describe how mom lunges for the knife and when she does it's on again. >> finally, said the girls, they overpowered their mother. who stopped struggling. and mood that she was cold. so they put her in a warm tub to try to soothe her. even though they said she she was still spinning mad and threatening. them >> kill me now, and or i'll kill you all. >> eventually, they said she, stop talking. drifted off in the warm water. and died. >> so, what did the da think after listening to the girls tale of self-defense against their mother gone berserk? >> did you believe them? did you believe everything he said? >> no. >> still don't. >> the idea that nikki launched an attack on her own daughters? difficult to believe, said the da. sheer nonsense is what nikki's mother called it. >> my daughter never hit her kids. they never had a spanking, or less. anybody knows nikki, knows that wasn't her behavior. >> it was very clear to the detectives who were the case, that in fact nikki was the victim of an unprovoked attack. she had at least 45 stab ruins. her spinal cord was almost severed. >> nikki fought for her life. we think she fought defensively. you can see where she's on her back, some of those times, fighting off people that are attacking her from above, with knives. >> as for the girls claim that they put their dying mother in the tub to keep her warm, as they watched her fade away, fiction through and through said, the police. >> we think she was dead before she was placed in the tub. or she would've bled into the water. the water would've been bloody. they put her in the blood water trying to wash off the crime scene. wash off the evidence. >> the true said the detectives, the girls were remorseless, defiant. remember how they sounded just after their mother's death? >> i want my mommy. >> i really want them to catch this person. please, god. >> listen to the little darlings when they didn't know they were playing for the cameras. >> are you available 59, 34? >> this was recorded in the back of the squad car just after their arrests. >> sweet little girls? >> they got -- evidence. they can do nothing with -- evidence. >> man, get real. did you find a murder with my fingerprints on it? or something? man, it be different if they said i did it. please do that. please find a murder weapon. thank you. >> they are aggressive. they are angry. they are combative. these -- -- dumb, dirty cops did this -- . >> oh, and one more thing. tucked away in one of the girls bedrooms police found this journal. inside childish handwriting a death sentence. there were notes to each other said the da, written just before the killing. she don't care. she selfish. we got to get rid of her. to which the other twin responds, that's what i think also. she gotta go, asap. >> it may be the most telling piece of evidence that the whole death of the mom may have been premeditated. >> still, the da worried may be a good offense attorney could spend the family serving that history. the juvenile court drama. nikki's two boyfriends, and somehow sell a jury on self-defense. >> it would've been an ugly trial. and i think to some extent it would've been a misrepresentation of nicky's life. >> so, he didn't like it much. but he let them plead guilty to the lesser charge. voluntary manslaughter. 30 years for each. not enough said nicky's mother linda. >> these children have killed my child brutally. and you're going to give them 30 years. they shouldn't even be able to walk the street. and i know these are my grandkids, but come on now! i mean, if they can do this to their mom, god help us all? >> the question is over and over again -- >> how everything about this goes against nature. how the person that provides for you and raises you and loves you, and gives birth you, how you could watch that person die in the bathtub. and lie about it. >> -- >> it was the reporter katie beck that brought the story to and atlanta both horrified and fascinated. she first secured access to all those police videotapes, exposing these pretty little liars for all the world to see. >> islam becomes clear that these girls have multiple personalities. that they can be whoever they need to be for their own purposes. that they can morph between fragile, disturbed, innocent teenager. into sort of this demonized criminal. >> those girls you know. the sweet little girls. what happened? to them? >> it's hard for me to even -- i don't know. >> and nikki's mother, lynda whitehead, carries the helpless grief with her every day. every sleepless night. without her daughter, without the granddaughters she thought she knew. >> i was so proud of them. and they would talk about what college they wanted to go to. and sorry. >> it's okay. >> so i'm sitting here and everybody is gone. >> that's an awful tough road. >> you can't even imagine. because every morning i wake up and think about my daughter and my grandkids. it's just a tragedy. >> one of a mother who dared dream that her sweet gemini twins would surpass her. who instead became their victim. >> that's all for this edition of dateline. i'm craig melvin. thank you for watching. -- ranking is as we come on the air tonight. mass shooting in jacksonville florida. as shots rang out in a store we >> have learned the attack was -- motivated. it is what the county said just moments ago. >> he killed three people before turning the gun on himself, taking his own life. out of the three individuals killed, and the shooter himself, there were no additional people who suffered gunshot wounds, we are not identifying that denise victim