She shook like someone with the start of parkinsons. Reporter what had killed her . Something at work . Something at home . Household items . Thats a possibility. Listen carefully. In this case, the most telling clue of all just might come from the victim herself. There seems like theres some suspicious things that have occurred. Reporter could this be murder . Do you think that someone might be trying to poison you . Thats a very unpleasant way to die. Yes. Reporter and could she help solve it . Youre describing kind of a murder in slow motion. Yeah, elaborate, diabolical. Its mindboggling im lester holt and this is dateline. Heres Josh Mankiewicz with poison. Reporter what was wrong with linda curry . Somethings happening to you, linda. Youre ingesting something thats in your body that shouldnt be there. Reporter she went to the doctor. A lot of doctors. And it wouldnt go away. And it would get worse. Nausea, vomiting, dizziness, confusion. Reporter medicine didnt seem to help her. You could have respiratory failure within a number of minutes. Reporter those who knew linda watched something unfold. But what exactly did they see . It would take 20 years to unravel this mystery. Linda curry, born linda kilgore, was six years younger than her sister, pat. Linda grew up to be a Southern California beauty. She loved the sunshine, horses and family. Pats daughter, ricki rycraft, looked up to her aunt linda. She would call me over to her house to go raid her closets and i would leave with my backseat loaded from the floor to the roof with clothes. Reporter she sounds like a lot of fun. She was a lot of fun. She was a blast. Reporter linda worked for the power company, Southern California edison. Thats where she met mary seabold. Where we really met was on the fourth floor, where we would go for break or for lunch. She ate like a horse and never gained an inch. Reporter dont you hate people like that . Totally. And it drew me to her. And then we came the best buds ever. Reporter but looks, generosity and brains dont guarantee happiness in love. Linda was married twice and divorced twice. She did choose guys that didnt seem to be a nice fit for the long term. Reporter and so she got her heart broken a couple of times. She got her heart broken i think more than a couple of times, yeah. Reporter but if her personal life wasnt going well, her professional life was. She climbed the ranks at edison, becoming the training coordinator at the San Onofre Nuclear power plant. And it was there that linda met a man named paul curry. He was 13 years younger than linda and worked as a nuclear physicist. Pauls boss, mike flower. Paul had an impressive resume . Yes, he did, and a good reputation. He had a senior reactor operator license, and thats not such an easy qualification to find. Reporter and just a few months before linda and paul started dating, he had won 24,000 on jeopardy . So, hes this younger guy. Younger guy. Reporter hes a gourmet cook. Gourmet cook, a pianist. Reporter hes in mensa. Mensa member. Reporter and hes a nuclear physicist. Nuclear physicist. All the right things. Reporter paul moved into lindas home in the picture perfect city of san clemente. They said their marriage vows in 1992. That part about in sickness and in health would be tested less than a year later. In the spring of 1993, linda came down with an illness that put her in the local hospital. Mary came to see her. She looked like a little girl in a big bed. She just looked so weak and not vibrant, like linda. Reporter frightening to see her like that . Yeah, you betcha. You betcha. Reporter her newly minted husband paul was sick, too, with many of the same strange symptoms. Both were weak, vomiting, like bad Food Poisoning or the worst stomach flu imaginable. Paul recovered quickly. Linda did not. We knew that she was very sick and that they couldnt identify what was causing the problem. Reporter paul kept a vigil by her bedside and kept their edison colleagues updated with daily emails like this. There still is not much clue as to the original infection, but if she continues to improve and gets well soon, i dont think it will really matter what the name of the problem was. I think we all can live with a mystery as long as lindas around to be mystified with us. How was paul when linda was sick . Very concerned. Reporter worried . Yes. Reporter eventually linda recovered enough to go home. Paul fixed her gourmet meals, drew her a hot bath every night, and soon linda went back to work at the San Onofre Nuclear plant. But months later, she was in the hospital again. Same strange symptoms. Linda, again, recovered enough to go home and back to work, but she worried about a relapse. She and paul planned to meet with some specialists who might be able to help. On june 9th, 1994, paul emailed mary. It was, gee mary, im really worried about linda. Shes wobbly and weak. Reporter paul wrote that she was mumbling incomprehensible stuff in her sleep about work and projects and meetings. And shes working all these hours. And shes working too many. And maybe, mary shell listen to you. Reporter when linda came home from work that day, she was tired and went to bed without eating dinner. A few hours later, the phone rang at mike flowers house. I answer it, he said, mr. Flower, this is the chaplain. And he said, can you come to paul and linda currys house . Reporter mike rushed over and found his friend paul, who told an awful story. How he woke up to an odd sound, found linda not breathing. He called 911, but by the time paramedics got there, it was too late. Paul was extremely upset. For hours i was basically holding him up and he was crying on my shoulder. Reporter grief, shock and at the bottom of it all, a question, what killed linda curry . When we come back, a medical mystery. Reporter this is really detective work isnt it . It is. It is. Her strange symptoms. Her sudden death. Lindas loved ones would wait years for an answer an answer that would come whats your full name . Linda curry. From linda curry herself. children laughing hes so cute what should we name him . gasps can we keep him . Please . Mom, can we keep him . Ahh both pleaaaase . New pet . Get scrubbing bubbles. Kill 99. 9 of germs, and destroy dirt and grime. You only need scrubbing bubbles disinfecting cleaners for 100 problem solved. We work hard so you dont have to. Sc johnson a family company. Dont walk on the grass no running no jumping the rules can wait right now just play freely in pampers cruisers they adapt at the waist, legs and bottom for our best protection and fit and all the freedom to play pampers dry spray . Ive never used one of these before. Thats fun. That is fun. Its already dry it dried right away. It doesnt feel wet at all right now. No wait time. This is great. My skin feels loved. Its very soft. Theres no white stuff. 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Well, did you know that playing cards with kenny rogers gets old pretty fast . You got to know when to holdem. Know when to fold em. Know when to walk away. Know when to run. You never count your money, when youre sitting at the ta. What . You get it . I get the gist yeah. Geico. Fifteen minutes could save you fifteen percent or more on car insurance. Everyone who knew paul and linda curry, knew that linda had been sick for months. An illness her doctors could never explain. And paul had been sick too. Now, suddenly, linda was dead. Pauls friend, steve whitley. Everybody was in such shock that i dont think the reason mattered. It was just, okay, we got to take care of our friend. Reporter how was paul . Griefstricken. Reporter so was lindas family. Her niece, ricki, remembers how paul changed the funeral arrangements to help them deal with lindas sudden death. He allowed the casket to be open so my mom could see her sister, wrap her mind around her sister being gone. Reporter linda was now only a memory. But shed left behind a perplexing medical mystery. What caused the Mysterious Illness that took her life . What were her symptoms . Diarrhea, vomiting, dizziness, fatigue. Reporter and it wouldnt go away . And it wouldnt go away. Reporter after lindas death, they discovered a medical chronology on her computer at work. Shed kept careful notes about her symptoms from the very beginning. It went back a year, to june 28th, 1993. She wrote, felt fine all day, worked late, had a salad for dinner, woke up in the middle of the night vomiting. A month later, july 24th, 1993, approximately one hour after eating i began vomiting. I became extremely weak and sweaty. Lindas best friend, mary seabold. She worked at a nuclear plant. She did. Reporter conceivable that maybe something she picked up there had something to do with that . No. Thats not what happens. Not unless youre in the reactor. Reporter and she never did that. No, no. Not at all. Reporter they considered other, darker possibilities. You know there are people who make themselves sick because they want to be the center of attention. Sure. She wasnt of that personality. Reporter possible that she was depressed . She loved her job. She had friends. Reporter she had the perfect husband . Perfect husband, a lot of nice high heels. What could she be depressed about . Reporter lindas autopsy was inconclusive. Her death certificate listed the cause as pending investigation. And sheriffs detectives did investigate. The interview is taking place at mr. Currys residence. Reporter in december 1994, six months after lindas death, they interviewed paul. Did you ever question them why they never found what was wrong with her . Sure. Well, both of us. We were making ourselves hysterical trying to figure out what was going on. Reporter like everyone else in lindas life, paul said he was puzzled and frustrated. Ive been a Problem Solver all my life, and for the last couple years there was a problem that i couldnt solve and its extremely taxing. Reporter and like everyone else, he wondered if postmortem tests would finally solve the mystery. You understand that theyre doing toxicological testing to find out yeah. Try to determine the exact cause of death. And they havent sent me any information. Reporter this is really detective work, isnt it . It is, it is. Reporter sabra botchjones is a forensic toxicologist at the Boston University school of medicine. She didnt work on lindas case, but in her lab, she often deals with the same challenges when finding out how someone died. Linda suffered from dizziness, weakness, vomiting after eating. Whats that sound like . Definitely the nausea and vomiting thats persistent suggests something thats actually being ingested that the body cannot handle. Reporter something ingested that the body cant handle. Thats what lindas friend mary seabold had thought all along. She says she shared her concerns with linda. Lets have someone go into the house and just check it. Lets see if theres anything foreign in here. Lets see if theres something in your lipstick, maybe something in your cream that you use every night. Reporter but she says linda never took that advice, never had her home tested. Now they all waited for the toxicology tests on lindas body. And sure enough, the lab that examined lindas samples did detect and identify something quite curious. Linda currys body contained lethal levels of nicotine, which only deepened the mystery. Because, according to everyone who knew her, linda curry did not Smoke Cigarettes or anything else. Never had. Never never. Reporter did that make sense to you, nicotine poisoning . Id never heard of it. She never smoked. How could this happen . How could this be . No, i was shocked. I was shocked. Reporter is it unusual to find nicotine in someones body . Its not unusual. We are exposed to nicotine either as a smoker or as a nonsmoker. Reporter there are more sources of nicotine than you think. Besides cigarettes, there are actually small levels of nicotine in eggplant and potatoes. It also used to be an ingredient in insecticides. If youre working in your garden and you were using an old insecticide that did contain nicotine you could possibly get it through absorption through the skin. Reporter enough to kill you . Yes. Reporter in sufficient quantities, she says, nicotine is a deadly poison. In the beginning the individual may experience some nausea, vomiting. Thats going to be followed with tremors leading to convulsions and then complete respiratory depression, leading to the death of the individual. Reporter you stop breathing . You stop breathing. Reporter that sounds like a very unpleasant way to die. Yes. Reporter linda didnt garden either. And the coroner didnt believe that amount of nicotine got into her body by accident. So he classified her death as a homicide. You kept waiting for that investigation to go somewhere. Exactly. Reporter never did. Never did. Reporter detectives could not determine where the nicotine came from or how it got into lindas system. Months passed, then years. Lindas niece ricki rycraft spoke often with the lead detective, and one day heard something that shocked her. He seemed to be inclined to think that she had committed suicide. Reporter that might have been the end of the story, were it not for this man, at the time a determined student. He never met linda curry, but one day hed know everything about her. Coming up we went back through every interview with every witness a new team makes a new discovery. The nurse came back to the room and found the iv bag had a discolored fluid in it. Reporter in 2006, when the name linda curry caught the eye of an Orange County prosecutor named Ebrahim Baytieh, the case was as cold as it could be. Linda curry was already dead by the time you even came to work here. Linda curry was dead when i was in law school. Reporter nevertheless, baytieh and sheriffs investigator yvonne shull decided to take another crack at solving the mystery more than a decade after lindas death. We went back through every interview that was conducted with every witness. Reporter they also went deep into lindas medical records, and found out something very strange had happened during her first hospital stay. The nurse came back to the room and found the i. V. Bag had a discolored fluid in it, and changed it out. Reporter after that discovery, shull learned, linda became seriously ill, ending up in the icu. Eventually, she got better and went home. But then, four months later, she was sick again. Back in the hospital. And again, something odd occurred. At that hospital, the i. V. , the port on the i. V. Which is where they do injections into, an i. V. Was broken. Reporter this is a different hospital. Different hospital, different staff. Reporter had someone tampered with those bags . Could it have been poison . That was never clear. They tested everything. They couldnt tell. Reporter normal toxicology tests, normal hospital testing wont pick up nicotine unless youre looking for it . Unless youre testing for it, correct. Reporter the incidents were as troubling as they were mysterious. No Surveillance Video or security tape showing anybody doing it . No. The only common denominator is linda and paul. Reporter so linda was getting the treatment and paul was right there by her side as a dutiful husband. Yes. Reporter paul, the dutiful, doting husband. As they reviewed old interviews and conducted new ones, baytieh and shull quickly picked up on a theme. Lindas friends and family didnt much like him. Her niece, ricki. There was this arrogance about him. Reporter remember, paul was a physicist, a member of mensa, a jeopardy winner. And apparently he didnt keep any of that a secret. He was on some other social level than we were. And so, i felt he looked down his nose at us. Reporter he thought he was better than you were. Yeah, definitely that. Reporter linda, of course, loved pauls intelligence and the way he spoiled her. But when linda got sick, her mary got suspicious. She was telling me that, oh, paul is now making me these salads and hes making me this new dressing. And you know what hes doing, mary . Hes such a good guy. Hes drawing a hot bath for me right after i eat. And hes making me soak. And shes getting sick. Reporter and you think that the salads and the homemade dressing and the hot bath all has something to do with this . I think, hes a nuclear physicist, right . Yeah, hes mensa. Hes a smart guy. I think he was trying different things. Reporter things like nicotine . Was that even possible . Well, not impossible, according to toxicologist sabra botchjones. Conceivable that if you serve somebody a spicy or savory enough dish that they might not notice that there was a significant amount of nicotine in there . It could be possible. Reporter if you introduced it somehow in someones bathwater and put in some perfume or scented soap of some kind. May be able to mask the any odor that it may produce. Reporter so, theres a lot of ways that you can get nicotine into your system without noticing it . Possible. Reporter its worth remembering that paul got sick at the same time linda did, so whatever affected her seemed to affect him too. But as friends and family watched paul get well and linda get sicker, their suspicions hardened. You always immediately suspected paul of having done something . From the first phone call. I thought he definitely was trying to kill her. Reporter other people thought the same thing. Absolutely. Reporter nobody called the police. There was no proof. Reporter still, mary says she tried to warn linda. I told her she had to leave. Reporter and shed say, what, youre seeing things . Shed say, mary, hes a good husband. He wouldnt hurt me. Reporter those worries from friends and family, the mystery illness, the questions about the i. V. S, a lot of suspicions, but no evidence. And certainly no witnesses. Except one. Whats your full name . Linda lee curry. Reporter linda curry herself. And what she had to say was breathtaking. Coming up how have you been feeling . Well you know i would either feel great exactly what was on those interview tapes . If somebody were trying to do something to you if they were trying to poison you, who would try to do that . Linda