teresa sievers? it's very hard to find someone that truly you feel cares about you as a human. you know, there's something about her caring about my family, about my career, about my life. so you don't find that very often. it means pain relief without surgery, pills, or injections. dennis murphy: so how is it that the dreams of this adored physician and aspiring tv doctor never came to be? well, settle back, because there's a story there in, an exceedingly grim one. go back to june 29, 2015-- another muggy monday dawning in the southwest coastal town of bonita springs, florida. teresa had been away for the weekend for a family celebration up in new york with her husband mark and two young daughters. teresa's mother had turned 75. but she flew home early to see her monday morning patients, leaving her husband and daughters up north. these security images, so poignant now, captured dr. sievers arriving at the airport in fort myers sunday night. when she failed to show up for her morning patients, the c

teresa sievers even today on those youtube videos promoting health, healing, and a good life. she had helped so many, spreading her gospel. tragically, her message, like her life, cut short before she was finished. hello, i'm craig melvin, and this is "dateline." hello, i'm craig melvin, and this is "dateline." i had to do it. you're dead. rachel brady: ever since i heard it, it's been replaying in my head over and over. [footsteps crunching] it was all very unbelievable. craig melvin: it happened on thanksgiving-- two teenagers missing. i just buried my head into my hands, and i started to cry. craig melvin: where they were and what they did would launch a terrifying case. why did this have to happen here? craig melvin: with a deadly end. nobody's leaving until we figure out what happened. craig melvin: a man at home, alone and afraid. what would you do if you felt in danger? they were really attacking his home. you have a right to protect your home, and to protect yourself. he planned, he prepared, and he was determined to kill. craig melvin: the most chilling detail of all,