she loved us. >> it cryptic community. where is she? what happened to her? who is responsible? >> we went into full investigation immediately. >> quite honestly, it is possible she is alive. >> he was watching her and following her. >> deeply creepy stuff. deeply criminal acts that were recorded. >> yes. that's his favorite thing, collecting women. >> my heart just sunk. >> how many other times has he done this? how many other women has he done those two? >> a young nurse vanishes in a mystery stain -- >> he brought us to the back. >> and we all looked down. >> we just gasped. ♪ ♪ ♪ >> the front range of the vast grassland -- this woman, tina -- >> the question get set for the next two decades, where are you? >> the search is begin, yep. >> where are you? >> and we searched, oh gosh, probably over 50 different locations. >> officially, she was a missing person. had been for more than 20 years. but the authorities, like then detective brad goldschmidt, couldn't accept that she was a runaway looking for a fresh start. he'd spend more hours than he could count searching gravel pit's and train -- for missing tina. >> so 14 was just a small little woman, and a lot of colorado? -- >> i thought we would never get her. he >> they couldn't prove it, but it was the consensus of law enforcement that the young nurse was the victim of foul play. her sister susan didn't disagree. >> it just wasn't fair. you know, she would've been so good for the world. >> and she had an unshakable theory about who made her sister disappear. >> evil. he's just evil. >> did you think, i now have hannibal lecter here? >> yes. this guy is by far the worst criminal i've ever investigated. and that's 21 years of gang investigations under my belt. i am certain he convicted a felony a day for the majority of his adult life. and he got away with it constantly. >> the problem with the missing teen investigation was this. how could prosecutors convince the jury she was murdered if you couldn't even prove beyond a reasonable doubt that she was in fact dead? >> take it off, what were the usual ingredients were missing here? >> we did not have a victims body. we did not have any kind of confession or admission by suspect. we didn't have a crime scene. we don't have any physical evidence. >> carol, a nurse and coworker of tina, spent weekends looking for her vanished friend. only to be startled away later with a stephen king-like vision. >> i would be in a remote area, and she was in a shallow grave in my dream, and she would sit up zombie style and she was trying to tell me where she was buried. and i always wondered, is that really her telling me? or is that just my way i'm coping with this? >> eventually, there would be a grave. but it wasn't shallow, and it wasn't out in the prairie. but there's so much to know before i tell you about that. >> go back to a time in america when kids would play outside on summer nights till the street lights came on. in windsor, colorado, you might have met the -- there are a lot of them. there's annie -- >> nine kids, seven, four boys. i'm the youngest. number nine. it was kind of like boot camp as. soon as you get to a certain age, here's how you do laundry, here's how you clean. >> that michael was an ex marine in a former city cough. mom, mary ellen, worked at the campus bookstore and nearby greeley. annie's sister, older by 13 years, was tina. was she something like an older aunt to you or something? as much as a sister? >> she was very much a sister to me. she cared for me, she played with me, she would play with us in our clubhouse. she would do obstacle courses with us in the backyard. always very attentive to us. >> personality, what made her happy? what do you see her doing when you see her smiling in her mind? >> being with family made her very happy. she loved us kids a lot. >> tina was a little shy, but a competitor in high school basketball and track. finding suitable boyfriends was where she stumbled some as sister susan recalls. mom and dad did not approve of two of her young studies. >> she kind of found the ones that needed help and she thought she could help. them >> but college gave her footing and studies in nursing gave her direction. that's where she met a guy taking classes to become a radiology technician. his name was john sandoval. >> what did your parents think of? john >> my parents liked him. he was kind of older than. tina >> they were sharing an apartment greeley, colorado, with her new boyfriend john. we -- thought it was all very exciting. >> he was quiet, but sociable at the same time. he seemed really nice, well mannered, very polite to everybody. >> complimentary of your sister? >> oh, very much. >> i really looked up to the relationship a lot. and i thought there were good fit. i thought was a fairytale, you know. >> and he loved going over to tina and john's to play chinese checkers and mess about with their no dog cody. tina had broken out of her strict mask on sunday catholic upbringing. >> what is your childhood mind make of your sister and your boyfriend? >> i don't think any my other siblings had lived with somebody before, so it was a whole new experience. >> and it was going to be a wedding? >> we were in the wedding. >> john tina had found a chapel up in the rockies to exchange their vows. >> i was a -- girl along with my sister teresa. our sister kelly, who is the oldest, was a bridesmaid. and it was just a nice little chapel, small ceremony with his family. he was really quick. >> happy day? >> happy day. >> very beautiful. we took a huge group picture out front of the chapel afterwards. >> john toasted the bride at the reception. -- our families getting bigger and welcome to the family. >> tina open presents. >> this is from an a! >> it's a book. >> and he remembers terrain around the reception hall -- it's >> a time to be gleeful and happy and enjoy the time. >> john's cousin and best man, jessie, he gave a little speech. >> i know there are going to do well for each other. and thanks again for everybody. >> jesse, for some reason, set and he's tea on edge. >> he was extremely quiet. kind of made me nervous. i just had a feeling about him that i couldn't put my finger on. >> you wonder what was going on, or? >> yeah, yeah. he didn't sit right with me. i kind of avoided him. >> and so, after the toasts and happy tears, the new mr. and mrs. were off to cancun for a mexican beach honeymoon. the snapshot shows a happy couple. and he was thrilled to get a souvenir. >> cancun t-shirts. and that was pretty cool because we have never been out of the country or even flown on a plane. and here's tina going on a cool vacation, you know? >> so a suntanned tina returned to her nursing studies. happy forever after? not exactly. >> i didn't see it coming. didn't notice anything off kilter, and then suddenly, we were moving tina out into a new apartment. >> coming up -- >> she wasn't very forthcoming in the beginning. i knew they were having problems. and she had concerns, but she wasn't telling me. >> me and my sister were really scared. >> had tina been keeping a secret? the mystery that would take 20 years to solve was just getting started. >> there was nobody, there was no crime scene. there were no witnesses. quite honestly, it is possible she is alive and she's living somewhere else. >> when dateline continues. i've never been healthier. shingles doesn't care. but shingrix protects. proven over 90% effective, shingrix is a vaccine used to prevent shingles in adults 50 years and older. shingrix does not protect everyone and is not for those with severe allergic reactions to its ingredients or to a previous dose. an increased risk of guillain-barré syndrome was observed after getting shingrix. fainting can also happen. the most common side effects are pain, redness and swelling at the injection site, muscle pain, tiredness, headache, shivering, fever, and upset stomach. ask your doctor or pharmacist about shingrix today. kiddo: mom, can i go to the movies? 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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. nature's bounty hair growth. clinically shown to help grow thicker, fuller hair with just one capsule a day of advanced hair complex. conquer hair thinning... ...and fall in love with your hair all over again. only from nature's bounty. susan: she was really in love in the beginning. narrator: what do you think the glue was there? susan: i think the way he talked to her just so gently. >> she was really in love in and he just treasured her and he the beginning. >> what do you think the glue was there? >> i think the way that he talked to her just so gently and he just treasured her, and he made her feel really special. and she hadn't felt that way for a while. she'd been treated like dirt. >> come a long long way, right? >> he called her kitten. and was constantly like you are so beautiful, you are so beautiful. i can't believe i'm with you. >> he might have been in eloquence we talk, or but john seemed to have trouble holding a job. he never did finish his radiology class, and found a string of part-time hourly jobs. working at a liquor store, a customer care calls enter. about two years into the marriage, tina's sister susan could sense that something was off. >> she was feeling like maybe john wasn't who she thought he was. >> did you scratch around on that? >> a little bit. she wasn't very forthcoming in the beginning. i knew they were having problems. and she had concerns. but she wasn't telling me a lot of what she already knew at that point. >> to, it turned out, had been keeping a secret about her marriage. and she wasn't ready yet to disclose the humiliating truth, not even to her sister. nursing school, meanwhile, was going very well. she dove into the field and found her passion, caring for other people. tina soared. one of tina's fellow nursing students was carole chauvin. she was scared to meet her first patient as tina was confident. >> she literally push me in the door. >> you can do it. you need a pep talk? >> she physically pushed me into the patients room. so i think when it came to nursing, she was a natural. >> in command? confident? >> confident, not bossy in any way. but she knew what she was doing. >> but carroll knew almost nothing about tina's life away from nursing school. the shy teenager had become the nose in the book student, and didn't socialize with her classmates. >> sister susan had married by then to, and she and her husband ended up getting an apartment just down the street from john and tina. >> so we could easily walk back and forth and see each other. and i had my daughter at that time. and she was a toddler. and my sister loved children. >> susan would take her little girl to see and tina for coffees that became a heart to hearts. susan confided that she was unhappy in her marriage just as tina was restless in hers. >> so she was actually really encouraging me to get out of my marriage. and so, she really wanted to help me. and she kind of made the lead before i did. and started filing the divorce paperwork and moving out into her own place. >> by summers and 1995, tina and john were done. >> when it cracked, what was the thing? >> i think it had been going on for quite some time before i knew about it. from what she told me later, she was confronting him about what things that she was finding out about him. he's not a good person. >> kid sister annie was clueless about why tina and john were almost prince charming were splitting up. but there she was helping to log boxes from the old place to the new apartment. and john was there. >> he helped as well. and i asked him, why is tina moving out? what's going on? and he said, oh, don't worry about it. we just need a little bit of space. we'll be back together soon. >> did you think that was likely? >> i thought it was. i admire their relationship. i idolized it. i believed in it. >> you wanted that life for you? >> yeah. >> but john sandoval soon plummeted from her list of admired man because of something that just happened after they finish getting team moved. >> he took my sister and i back to town and he got us some ice cream cones and took us to the lake. and then, he started driving down the boat dock into the lake. >> the boat launch, the ramp? in the vehicle? >> yes. >> and me and my sister were really scared. we didn't know what he was doing. >> was it a goof? >> it was a different side of him that i never seen. he seemed to be getting joy out of our terror. >> this water is coming up over the hubcaps? >> yeah. and we didn't know what was going to happen. >> and then he stopped and backed up and took us home. and that was it. >> did he become a category of a different person after that to you? >> yeah. >> the john you idolized wasn't necessarily the same guy? >> yeah, he scared us. >> scary, and john sandoval were just getting up to speed. >> coming up -- >> my jaw drops and i'm like? what >> a separation and an obsession. >> she would look out over the balcony and its car would be out there for hours. >> his car? they're separated? he's checking her out? he's talking? her >> right. he was letting her know that he was watching her. and following her. >> when dateline continues. which is now more important than ever. ♪♪ it■s beginning to look alot like savings! blendjets holiday sale is on now! give the gift of convenience the blendjet 2 portable blender is perfect for everyone on your list. even that picky relative who hates everything. and dont forget the accessories! theyre all on sale! dont wait! our most popular colors and patterns will sell out! go to blendjet.com and take advantage of our holiday sale now. having triplets is... -amazing -expensive. so, we switched to the bargain detergent, but we ended up using three times as much and the clothes still weren't as clean as with tide. so we're back with tide, and the clothes are clean again. 3x the laundry and get a tide clean. it's got to be tide. about two years ago, i realized that jade was overweight. i wish i would have introduced the fresh food a lot sooner. after farmer's dog, she's a much healthier weight. she's a lot more active. and she's able to join us on our adventures. get started at betterforthem.com the power goes out, and we still have wifi to do our homework. and she's able to join us and that's a good thing? 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>> you know, tina was the best. if there was a call like going off, she's the first to pop up and go get it. and she, you know, her patients liked her. everyone liked tina. she was fantastic. >> it had been a momentous year for tina. she got her degree, left her marriage, and now had successfully kicked off her career in nursing. she was a 23 year old woman about to be divorced and living alone in a cool apartment that was all hers. >> i think it was almost a huge weight had come off her shoulders. she seemed to smile more, i think. and open up kind of like a butterfly. >> old tina rarely socialized with her classmates, but with carols and courage meant, she now stepped out and let down your hair. >> she finally wanted to go have fun and join her friends and it was so nice to see her open up and tell more about her life. and probably the most profound thing that happened the night that we went out, she came to my apartment to get ready while she was at my house, i said, you know, tell me more about john. and she said, well, john has the disease. and i said that to, what do you mean? >> he has voyeurism, she said. i don't know what that meant at the time. what's that? she said, well, he will see a pretty girl the grocery store and i feel compelled to follow her home. and he might washer for two or three days. and you know. she said it super calm like that. >> like this is a normal kind of story to tell? >> my jaw drops and i'm like, what? that's a stalker. she said, no, no, no, you don't understand. it's an illness. he can't help it. >> a disease of stalking? >> a nursing school, we learn about all the personality disorders. i don't ever remember learning that it was any kind of illness. >> my husband is a guy who follows women around? >> right. >> carol led the stunning remarks slide as she and dina went to a club that night and their friendship was born. the topic of her about to be axes so-called disease came up again. >> i said, so do you think that john ever watches you? >> and she said, yeah, same thing, real come about it. she said she would look out over her balcony and his car would be there for hours just watching. >> his car? >> his car. >> they're separated? but he's checking her out? he stalking her? >> right. >> did that creep her out? >> she said it matter-of-factly. she didn't seem afraid at the time. >> once she'd made the decision to leave, tina told the same stories to her sister susan. tina finely confided that she had married a peeping tom. he'd leave their bed in the middle of the night, she said. to crawl backyards