♪ this is "nightline." >> tonight, two weeks of dating turning into three years of stalking. >> i would regularly receive 60-plus texts a day, 100 emails a day. it was not uncommon. >> after the relationship ends, a wounded lover seemingly lashing out. but nowhere to be found. >> a lot of people thought she'd just gone off her meds and she was, you know -- just went off the deep end and left. but i knew that that's not what happened. >> the chilling mystery. is someone impersonating that missing stalker? to cover up another crime? >> the changes from a missing persons investigation, now it's a homicide investigation. >> "nightline," "tangled web," will be right back.

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so millions more students can continue to get the tools they need to build a future of unlimited possibilities. "nightline" continues. here now, byron pitts. >> most homicides are dark. this one was bizarre. >> what do you do when somebody invades every space of your life? >> reporter: in 2012, dave krupa, a newly single father of two, moved to omaha to start

over after separating from his longtime partner, amy. he looked online when he felt ready to start dating again. >> i didn't know how to venture back into the dating pool. >> reporter: the first person he met was shanna elizabeth golier, who goes by liz. she was also a single parent with kids around the same age as dave's. >> liz loved taking selfies and sending them to her friends. >> she was sexy, she was bright and shiny, and she was very engaging. >> reporter: dave says he was up front with liz when they met. he was dating several women and not looking for a commitment. >> i was kind of going wild, just -- you know, being free for the first time in a long time. >> reporter: six months after meeting liz, another single mom walks into the auto repair shop where he worked. 37-year-old carrie farver. >> when we looked at each other, there was a little spark. >> reporter: she'd grown up in small town macedonia, iowa, was extremely close with mother nancy. >> she had a lot of friends.

she was very gregarious. >> you noticed carrie when she walked into a room. she had a laugh, she had a smile, you were drawn to her. >> reporter: she became pregnant with son max at 22, deciding to raise him alone when the relationship with max's father didn't work out. >> she just doted on him all the time. >> reporter: cari had mental health issues, was diagnosed with bipolar disorder in her 20s. >> there was a couple of times when she just -- she would stop taking the medication because she said, "mom, it just -- i feel like i'm just numb." >> reporter: by the fall of 2012, cari was in a good place. she landed a job as a computer programmer in omaha. >> super excited. talked a lot about how that was going to be a life changer for her and for max. >> reporter: on her first date with dave, cari said she too wants to keep things casual. >> i felt like i hit the jackpot, i couldn't have wrote it better. >> one slightly awkward thing,

the night of dave and cari's first date, liz goyer came by dave's apartment to pick up things she left there. >> i walked cari out the front door, and she walked right by liz. they probably saw each other for six seconds. >> reporter: cari's office happened to be around the corner from dave's apartment. despite only dating for two weeks, she decided to stay with him while she was working on a big project instead of making the hour commute from her home. around 6:30 a.m. on november 13th, 2012, dave left for work early, kissing cari good-bye. it would be the last time he'd see her. later that morning, he gets a message from cari. >> she texted me, "let's move in together." which was very left field. because we had already talked about that not happening. as soon as i can are i texted her back, "i'm not interested, i can't do that." and almost immediately i get a message back that says, "fine, i hate you, i'm dating someone else, i don't want to see you

anymore, go away." lots of profanity. i didn't know what to think. i was blown away. >> reporter: later that day, cari's mom also got a strange text from her saying she was taking a new job in kansas. >> so i texted her back, and she would not call me and talk to me. >> reporter: carivity's son had been staying with nancy, who became alarmed when cari didn't show up to take max to a family wedding. that's when she reports cari missing. >> a lot of the people thought she'd just gone off her meds and she was, you know -- just went off the deep end and left. but i knew that that's not what happened. >> reporter: meanwhile, dave was still getting a barrage of angry messages from cari. >> they were bad. they were just all about how bad of a person i am. >> cari's rage seems to be f focused on his on again, off again ex-girlfriend, liz, who he had dated before cari. which is confusing to dave.

because cari seemed to be so unaffected by her first interaction with liz. >> reporter: liz told dave cari was harassing her too. >> she wrote to liz, "if you don't keep your hands and lips off my man, i will hurt you." >> i would regularly receive 60-plus texts a day, 100 emails a day was not uncommon. >> reporter: eventually cari seemed to be flat-out stalking dave. >> on one specific occasion i was sitting in my la-z-boy with my feet up, watching tv, trying to relax. it's nighttime. i get a text saying, "i see you, you're sitting in your chair with your feet propped up, wearing a blue shirt." those things were true. >> reporter: dave and liz begin to call her crazy cari. they get back together, united by their shared trauma. >> it was extremely common for us to be hanging out and both of our phones would start blowing up with text messages and emails from cari. >> reporter: nine months after

cari is last seen, liz called dave in a panic saying her house has been burned down. >> fire trucks all up and down the street, firemen walking around, there's hoses, they're pouring water into the place. >> luckily her children were not home, but many of her belongings were still there. including two dogs, a cat, and a snake. and they all were killed in this fire. >> from what i've seen so far, looking inside, this is -- pretty obvious this is an intentionally set fire. >> the guy that i'm seeing, he has a girlfriend, she's been stalking me since summer. >> i felt very bad for liz because i felt like i brought this crazy person into her life. >> reporter: as weeks turn into months, cari's mom, nancy, becomes increasingly worried. as her daughter fails to show up for the holidays, max's birthday, and her father dennis' funeral. >> i had a very, very, very vivid dream that dennis had come to me and he said, "nancy, don't

worry about her, she's with me." >> reporter: max decides to reach out to his mom over facebook. >> all it said was "hi." she immediately wrote him back, "hey, little man, how are you?" he asked her to answer three questions to prove that it was really her. and she never responded to that message. >> then cari posts on facebook, i've answered enough questions to prove myself, i'm not missing, i just don't want to come home right now. one of the things about these text messages, they don't look like they're written by cari, they're filled with spelling errors and grammatical errors. her mother said cari never would have sent messages like that. >> reporter: by spring 2015, the missing person case cari's mom filed 2 1/2 years earlier had gone cold. detectives ryan avis and jim doty had heard about the case around the office, volunteered to work on it. they examined the case file with a fresh perspective. doty investigating as though

cari was dead, avis trying to prove she was alive. >> cari's checking account had no activity. it's not normal for adults to just up and leave and literally spend no money, no one's seen them -- it just doesn't make sense. >> the key to the case at this point is figuring out if cari is not alive, who has been actually sending these messages to dave and to liz? >> reporter: detective doty focuses on liz galier. >> all of a sudden these this focus of harassment. her name was all over the reports. >> reporter: during the investigation of her harassment claim, police downloaded the contents of her phone. they reviewed those files and found a photo of cari's car. >> we look ed at the meta date f that file, taken a month before police recovered her vehicle. somehow liz knew where cari's vehicle was before law enforcement even did. another thing on the phone download, six calls that were made to cari's residence.

using the star 67 prefix to disguise the number. liz was calling cari six times. we found an email that cari had sent to dave that consisted of a picture of a woman who was tied up. we found that picture of that bound woman in liz's phone. the meta data showed it was taken from liz's phone. >> they realize that liz had put duct tape on her own mouth, tied up her own hands, crawled into the trunk of a car. coming up -- >> all of the investigating they had done was leading them to the idea that cari farver was dead. and liz had been impersonating her this entire time. when moderate to severe ulcerative colitis persists... put it in check with rinvoq, a once-daily pill. when uc got unpredictable,...

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"nightline" continues. here again, byron pitts. >> reporter: by the spring of 2015, 37-year-old single mom cari farver had been missing for 2 1/2 years. the only signs of her were thousands of menacing texts and emails. police were beginning to suspect liz galier was behind all those messages and that cari might actually be dead. as the investigation progressed, they share their theory with dave krupa, cari and liz's ex-boyfriend. >> the police had come to me and said, liz is the culprit. but i still hadn't seen any evidence myself. so i was either trying to ignore the whole thing, or trying to understand how this person i

spent so much time with could be this other person i didn't know. >> reporter: on december 5th, 2015, liz calls 911 to report an emergency. she's been shot in the thigh while taking a late-night walk in the park. >> my leg is soaked with blood. >> is the assailant still nearby? >> i don't think so, i took off running. >> reporter: liz tells police she thinks her shooter was ava flora, the mother of dave's children. police don't buy it and amy had an alibi and was cleared almost immediately. >> one of the schemes to bring dave back into her life and make herself look like a victim. >> reporter: days before the shooting liz had asked to file a harassment charge against amy. >> all these years she thought she was harassed by cari, but now she thought it was amy pretending to be cari. >> they only dated two weeks. i don't understand why a person

would still be stalking him three years later. >> reporter: she allows police to download and extract the information on her phone and they give it to a forensic digital expert. he spends thousands of hours trying to determine where all the messages allegedly sent by cari were coming from. he eventually traces them to liz galyer, not amy flora. >> liz signed up for upwards of 20 or 30 fake addresses that say they're cari farver. every account that we look at, there's always a connection back to an account she has, a device she has, or so her house. >> he discovered part of her ruse, liz was using an app which allowed her to send messages and receive them at a later time. >> she was able to send messages pretending to be cari, and they would arrive while she was sitting on the couch next to dave. from dave's point of view, liz couldn't have sent it because she was sitting next to him the whole time. it gave a perfect alibi to liz. >> reporter: investigators bring liz in for an interview, telling

her they're looking into the disappearance of cari farver, developing a ruse that they fake they found her remains. liz points to dave's ex, amy flora, as the cull pit. >> i'm sitting across from liz. i knew most likely she was a murderer. i knew in order for to us solve this, she's going to have to believe that i genuinely thought amy was responsible for all of it. >> reporter: investigators know amy is innocent. but they tell liz they need her help in getting amy to confess to cari's murder, hoping liz will incriminate herself in the process. >> it took a few days for liz to play into their hand. >> reporter: liz starts forwarding emails she says were from amy. investigators press her to get specifics on how cari died. >> when i met crazy cari, she would not stop talking about dave and him being her husband. she fried to attack me, but i attacked her with a knife. stabbed her three or four times in the chest and stomach area, then took her out and burned her. i stuffed her body in a bar began can with crap.

>> reporter: in another email liz reveals the crime scene. >> she writes, i really did kill cari, and i did do it in her own car. >> reporter: police then search cari's car. >> we opened up this door, pulled out the passenger seat, pulled off the fabric, that's where we found that big, red stain on the bottom of the seat. the positive test for human blood. >> reporter: a dna test of the blood showed it was a match for cari farver. >> it's a huge moment. it changes from a missing persons investigation, now it's a homicide investigation.p>> re arrest liz for an unpaid traffic citation. >> take the handcuffs off her. >> reporter: allowing them to question her directly about her involvement in cari's case. >> we have a lot of questions that you need to answer for me. very important questions, you're in a very serious position here. her phone was at your house right after she disappeared. i want to ask you how you can explain that to me, please.

>> she's never been to my house. >> she definitely was giving me the old evil eye. >> for years and years, people have been sending emails under cari's fictitious accounts. the ip addresses show up to whose house? your house. >> i haven't had internet at my house. >> you definitely see a woman who thinks she's smarter than the police, who doesn't recognize that she's in a mousetrap. >> reporter: the detective then confronts liz, telling her he knows she wrote the so-called confession email. >> the finger's pointing right at you. >> i'm done talking, and i'm going to have my attorney. i didn't do anything. >> okay. >> reporter: meanwhile, detectives obtain a search warrant for liz's home. finding a camera and cam corder that belonged to cari. the camera had a video of cari taken just two days before she died. last known images of her alive. >> apparently somebody here in

the whopping metropolis of macedonia decided max's explorer is not the right color. we're going to see if we can fix that. >> reporter: she was documenting vandalism to her car, something investigators believe was done by liz. >> somebody thought they were quite the artist. >> reporter: armed with this evidence, investigators obtained a felony arrest warrant for the first-degree murder for liz galyar, december 22nd, 2016. liz retains defense attorney james martin davis, who waives a jury trial, making the judge the fact finder in the case. a nfew months before the trial started, dave remembers he's had a tablet in storage and gave the tablet who detectives, who discovered the sd card had once been in list's phone. it contained thousands of deleted images investigators were able to restore. >> i came to a photo that no one had seen before.

it was reddish. i wasn't sure what i was looking at first. but it turned out to be a human foot. human foot with a tattoo. >> the foot was decomposing. so this person was dead. >> reporter: the tattoo was the chinese symbol for "mother," the exact tattoo cari had had on her foot. >> this photo, it was -- it was shocking. it made me realize that liz golyar killed cari farver, and she's taking photos of her body. >> once we had this, i felt conf confident. >> reporter: in may 2017, the case went to trial with no body, no witnesses, and no murder weapon. >> it's a hard case to prove. it's a hard case to make. it's even harder to get a conviction. but the web liz galyar was weaving, she got caught in it. instead of being the spider, she became the insect. >> reporter: the judge found liz galyar guilty of first-degree murder. she was sentenced to life in prison.

liz declined abc news' request for an interview. >> if i could talk to cari right now, i'd say, i love you. i'm so glad that you were in my life. life. and i miss you terribly.tayed it needed to be here. ruby's a1c is down with rybelsus®. my a1c wasn't at goal, now i'm down with rybelsus®. mom's a1c is down with rybelsus®. (♪ ♪) in a clinical study, once-daily rybelsus® significantly lowered a1c better than a leading branded pill. rybelsus® isn't for people with type 1 diabetes. don't take rybelsus® if you or your family ever had medullary thyroid cancer, or have multiple endocrine neoplasia syndrome type 2, or if allergic to it. stop rybelsus® and get medical help right away if you get a lump or swelling in your neck, severe stomach pain, or an allergic reaction. serious side effects may include pancreatitis. tell your provider about vision problems or changes.

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