they were a mother and daughter who had both made mistakes, but there was no mistaking her love . >> she was not perfect , but she was perfect for me. >> and when her daughter became a mom, life itself seemed perfect, but not for long. >> called the sergeant and said, please tell me this isn't true and he said, i can't . >> but who wanted her daughter dead ? she had lovers not enemies. >> friends with benefits . >> the question for police, which fred was the father, and which the killer? >> it doesn't seem as if she always made the best choices in a man . >> no. no. single mom tori vienneau was surrounded by love. hello, and welcome to "dateline. single mom, tori was surrounded by love. in addition to her baby, dean, she had a boyfriend, a best friend, and a mother who adored her hear the grown-ups work as a team, caring for the baby. when tragedy stuck struck, tori realized, the only way was to fight for justice. here is josh mankiewicz with "complicated." in some families, the birth of a child can change everything . >> i would not have cared if we had a boy or a girl. it was going to be nice to have a little boy . >> dana was over the moon when her first grandchild was born. dean roberts came into the world september 26, 2005, weighing seven pounds, stretching out to 20 1/2 inches . >> he was beautiful. i was madly in love with him . >> her husband , roy, felt the same way. >> you were charmed. >> i was absolutely charmed. >> the baby's mother, dana's daughter, was just 21 and not ready for the challenges of parenthood. as baby dean grew from a newborn, to a happy infant with a sweet smile, tori grew as well . >> he was something we did not know was missing until he came and was one, big fat ball of love. and he opened up my daughter. it is like you could just see her heart go huge. it was a beautiful sight to see, watching her become a mom. i think every mom should be able to see that with their child. >> all of that joy turned to horror on the evening of july 26, 2006. >> my sister's roommate, i don't know what happened to her. >> take a deep breath so that i can understand. >> we tell a lot of sad stories here on "dateline." and while this one is it easy to tell, it might make you think about the relationship you have with your kids or your parents. what happened here in san diego turned a happy mother and grandmother into a fighter, who now wants the world to know what happened to her family, because to me she says, there are lessons here about life, about trust, and about the choices we make, and what she has learned might be a gift to someone else's family. >> before we go ahead, i want to ask you something, are you sure you want to do this? >> yes. >> because this is not going to be pleasant. >> but i think it is important. i think it is important to do. tori could have been any girl. >> of course, she was not any girl and she was dayna's . >> tori was the perfect daughter for me. she was not perfect, but she was perfect for me. from the minute she was born, we were two peas in a pod. she was perfectly flawed, i believe. >> most mothers probably would argue that there daughter does not have any flaws, perfect . >> no, she had flaws. >> dayna says, tori would get so focused on a goal, she sometimes would ignore signs of problems along the way. >> stubborn . >> yeah. >> and it does not seem she always made the best choices in men . >> no, there's a flaw there. >> tori's best friend members how tori always seemed to fall for the wrong guy . >> what kind of guys did she go for? >> to me, they weren't stable guys, guys that weren't nice to her, probably not nice in general . >> maybe that should not be a surprise , given that our relationships as adults often reflect the ones we witness as children. tori was barely 2 when her father left and cut all ties with her and dayna. and although stepdad roy, the old those issues later on and loved her, tori spent years dealing with her mother's issues . >> i will say this from jump , i am a recovering alcoholic, and up until she was 16, her life was fairly normal. and then, i crashed. i think i've always been an alcoholic, but it came to a head at this point . >> although you were drinking, you were functioning? >> i was functioning, but then i could no longer function. and then i could not stop. i woke up and i had a drink and i would take my daughter to school . >> drunk? >> yeah. yeah. >> as many children of alcoholics do, tori helped her mother cover up the drinking, hiding bottles, denying there was a problem. and for a while, that works, but at 16, tori felt she could not take it anymore. >> tori said, i love you, but i hate you when you drink and i will not watch you destroy your life and i found a place for you to interview at a recovery home, and you get one shot. if you fail at this, i'm not coming back. i need my mom back . >> that had to feel good , knowing that whatever mistakes you made, you raised a daughter who had that kind of backbone? >> i was very proud of her. >> so, dayna went to rehab for nearly a year. roy moved on to deal with the family's collapse in his own way. and tori , still in high school, worked with prince as a waitress. when dayna emerged nine months later sober, it was tori's turn to be proud. >> i wanted her to see, you could stand back up when you fall, and you could get your life back together. we put our marriage back together, put our family back together. >> over the next few years, tori and dayna become closer than ever and one day, tori came home with news of her own. >> i said, spit it out and told me, we will deal with whatever it is. she said, i'm pregnant. >> it should have been a happy beginning of a new chapter in the lives of both mother and daughter, but sometimes, as we told you earlier, the birth of a child can change everything. coming up, a phone call . >> he said , haven't the police contacted you? 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>> he was my little buddy, my friend. most times, he was my best friend. i watched him everyday while everyone was at work. >> dayna was amazed and amused by the three-way childcare. >> the three of them were comical and dean was just filled with love. >> but by the summer of 2006, when baby dean was 10 months old, tori and neil had broken up and daniel moved back home with his mom, although he continued to help out daily with dean's care, mom and baby were living in low income housing in a rough part of san diego. even so, grandma dayna still thought life was good. >> the last time you saw them me you were all in the pool together? >> she had gotten into the bikini, she was very proud of that. but she lost the baby weight. >> yeah. daniel was in the pool with dean, and roy was in the pool with dean, and dean learned how to splash. he realized, it was his hand making the water splash. he was roaring with laughter and thought it was just the funniest thing. i said, isn't our life perfect? we've come full circle. doesn't that sound like music from heaven when he laughs? >> that was what day? >> that was sunday, the 23rd of july. >> three days later, on a wednesday night, dayna was struck by a news story about a mother and her baby . >> that night, i saw on the news i think they set a mother that was 27 and a child that was 8 months had been murdered. >> one of the roommates came to the south complex just before 9:00. >> i said a prayer for that family, that is horrible. i went to bed, thought nothing of it. >> the next day, dayna got a called from tori's workplace, dana-- tori had not shown up. she got a call from the daycare, baby dean was not there. she called daniel. daniel in an almost matter-of- factly, told dayna the worst news she had ever heard . >> he said, haven't the police contacted you? i said, why would the police be calling me? and he said, the mother and child on the news last night was tori and dean. >> it was too terrible to hear. >> i was engulfed in heat and i know when i went back to the phone to me the line was dead. >> dayna called police to find out more. they confirmed that both her daughter and grandson were dead. they held back the details because it was a gruesome crime. but soon enough, dayna would hear it on the news . tori had been beaten. both she and 10 month old baby dean had been strangled. dean was still in his crib . >> i called the sergeant and said, please tell me that this is not true. he said, i can't tell you that. and then, the nightmare began. >> by the time dayna had learned what happened to her baby grandson and daughter, police had already gone through the apartment, dusting for prints, searching for dna, looking for anything that might explain this double murder. >> first of all, what could you tell with the crime scene? >> just that it appeared to be a violent assault . >> lieutenant kevin rooney supervises the san diego police homicide unit. >> there was no forced entry. it was not uncommon for tori and her two roommates to leave the door unlocked. >> sexual assault, robbery? what do you think marks >> she was clad in a brawl, but there were tears to her clothing, so at the beginning, we were open to the possibility that this was an attempted rape. >> but why kill a 10 month old child that would not be able to testify? >> exactly. a 10 month old boy who does not speak. >> right away, the cops started bringing in tori's friends here too you did not kill her, did you? >> no. >> tori's best friend, daniel the one who had taken such good care of baby dean was also brought downtown. >> your typical investigation? >> yeah, little tiny room, lights on me, talking. they asked me where i was. >> took your fingerprints? >> yes. >> confiscated your cell phone? >> yes. >> you felt like a suspect? >> i did not feel like they suspect the first night. that changed. that changed. that can't retain moisture. new pantene miracle rescue deep conditioner, with first-of-its-kind melting pro-v pearls... locks in moisture to repair 6 months of damage in one wash, without weigh down. guaranteed or your money back! for resilient, healthy-looking hair... if you know, you know it's pantene. everybody wants super straight, super white teeth. they want that hollywood white smile. 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. i think it's a greatjosh mankiewicz: tori and dean were gone. g to tori and dean were gone san diego detectives were piecing together tori's life. her mother, dayna, was planning a double final farewell. >> how do you get through a funeral for your only child and her brand-new baby? >> in a daze. in a daze. >> did you think about drinking again? >> never . >> because it seems like that would be a time when you would think about it. >> i would never dishonor her that way. i've made mistakes when she was growing up with my drinking. i was not going to make them in her death. >> but dayna was aching. she bought 43 books on grieving, hoping that would help her through living through the brutal murder of her daughter and grandson. she also looked for answers from the san diego police, but did not find them there, either. they told her, they were working the case, but nothing more, typical police procedure. frustrating? >> extremely. i was angry from probably week two. i felt that they were sweeping tori and dean under the carpet. >> so, this grieving mother and grandmother decided, she had to do something. maybe what she did was a form of therapy, or maybe it was just that she needed to scream something at someone, at the top of her lungs . >> we are not going away, we are just getting bigger and louder . >> she organized candlelight vigils. she worked with groups like crime stoppers and put out playing cards with tori and dean's photos. photos that said, please call if you know anything. in frustration, dayna held a press conference right in front of the headquarters of the san diego police . >> nobody deserves to die this way, certainly not an infant who could not get away, he could not speak. he was a baby! >> all along, she kept calling lieutenant kevin rooney, asking for details, and he was not giving up anything. >> when investigating a murder, there are many details, is that we will not reveal dayna was very angry. i understand it. >> she felt like you guys were getting nowhere. >> oh, she was very upfront about that. >> police were making progress, but progress in a real homicide really happens as it does in a tv crime drama. subpoenas have to be issued for things like cell phone records and computer hard drives. all of that would take weeks, if not months, to come in. what police did learn quickly about tori was that, she did not seem to have any enemies. she did, however, lead a very complicated life. tori was juggling not just work and motherhood, also three men. her boyfriend, neil springstube, her pal, daniel moen, and an old boyfriend, dennis potts. the cops quickly established that neil was in florida at the time of the murders. that left two. >> give me a brief sort of capsule on each one of them. >> dennis potts new tori since high school . they attended the same high school. they had what was described as a not exclusive relationship. for whatever reason, they were constantly drunk --drawn back to each other and did have a sexual relationship that existed over the years since high school. >> daniel moen never qualified as a boyfriend . maybe he was too nice, or just too shy. >> daniel knew her a long time. they had a child together. he described them as best friends, but he wanted more. i believe he loved her, but wanted a romantic relationship with her . >> and you knew that sometimes that may daniel, if not angry, at least unhappy . >> it certainly seemed of the three men in her life, he seemed to be the one on the outside looking in. >> however, in the weeks before tori was killed, things were beginning to change between tori and daniel. she seemed open to the possibility of making their relationship more than just friends, but she was not sold on it. >> she was not quite as into that whole idea as you. >> i don't think so. >> that bother you? >> no, not really. >> i don't believe you. >> i was upset she still talked to dennis and other people, but i knew how she was before, so i accepted her at how she was. >> daniel had spent years being forgiven of tori's weaknesses. dayna told detectives something did not seem right about daniel, specifically how he knew so much so soon about the murders. >> you had to, during that time, sort of flashback to how much more daniel was into tori then tori was into daniel? 's >> and it scared me in the way he knew they were dead in the way he told me they were dead. that kind of scared me, is what i told police. >> and in turn, police made sure daniel knew he was in their sites. >> the cop started coming at you really hard. frightening? >> after they told me i was the main suspect, yeah, a little frightening. >> they said, you are the main suspect mark's >> i believe i was the only suspect at that time. >> with the pressure on, daniel told cops, you did not do it. he shared with them unusual text messages he received from tori, a little before 7:00 p.m. that night. daniel said, it was soon after he got back to work after a break and also around the time police believe tori and dean were killed. >> that is why i left my phone with them that night. i got a lot of text before, some scary guy. >> there is some scary guy, standing by my car, looking into my place. daniel told police, that was odd, because tori did not think of her shared apartment as her place. he also told detectives about another text he thought was strange. >> dean was sleeping like a dead dog. >> was that the way she talked to mark's >> not at all . >> in an age demographic reduced to text messages, emotions as complex and different as love and hate, desire and friendship, tori's texted words to daniel are sort suddenly full of mystery. >> she texted you at one point, i love you, i want to be with you, and she says, my plans with dennis l through, why don't you come over to mark's >> yeah, that is funny because i never knew they would meet here it's >> tori told daniel she was going to see her mom, dayna that evening, but in reality, she was going out to dinner with dennis potts, her old flame from high school, the third man in her life. coming up, eight lover caught in a lie. >> that had to make you very suspicious. >> absolutely . >> when "dateline" continues. . discover caplyta. unlike some medicines that only treat bipolar i, caplyta is proven to deliver significant symptom relief from both bipolar i & ii depression. and in clinical trials, movement disorders and weight gain were not common. caplyta can cause serious side effects. call your doctor about sudden mood changes, behaviors, or suicidal thoughts right away. anti-depressants may increase these risks in young adults. elderly dementia patients have increased risk of death or stroke. caplyta is not approved for dementia-related psychosis. report fever, confusion, or stiff muscles, which may be life threatening, or uncontrolled muscle movements which may be permanent. common side effects include sleepiness, dizziness, nausea, and dry mouth. these aren't all the side effects. in the darkness of bipolar i & ii depression, caplyta can help you let in the lyte. ask your doctor about caplyta. find savings and support at caplyta.com. wanna know a secret? more than just my armpits stink. facts. that's why i use secret whole body deodorant for clinically proven odor protection everywhere. so i smell great all day, all hike, and all night. secret whole body deodorant. introducing kardiamobile. with kardiamobile, the fda-cleared smart device, you can take a medical-grade ekg in just 30 seconds from anywhere. every morning i check, make sure i'm in good shape. and it makes me feel pretty good about my heart condition. kardiamobile is proven