Transcript for 18-Year-Old Kidnapped at Birth Speaks Out About Accused Kidnapper
We have an exclusive interview tonight with the teenager who just days ago learned something that turned her entire world upside down. The woman she thought was her mom is instead allegedly her kidnapper. Police say sneaking her out of the hospital hours after she was born. Here's ABC's Eva pilgrim. Reporter: She was the only mother Alexis Manigo had ever known. Thank you. I love you. The order of the court months bond be set on count number one, kidnapping charge -- Reporter: 51-year-old Gloria Williams facing charges for allegedly kidnapping Alexis hours after her birth and raising her as her own. A devastating secret turning 18-year-old Alexis' world upside down. Anything I wanted to do, she was always there. Do you think about that ever? What your life would have been like? Don't get me wrong, I'm not saying they weren't going to be good parents. I'm not saying that at all. But it would have been a different life. Reporter: Detectives say Alexis, who her biological parents named kamiyah Mobley, was taken eight hours after birth in a Jacksonville, Florida, hospital. Williams, said to be posing as a nurse, allegedly entered kamiyah Mobley's hospital room and left with a baby in her arms, never to be seen again. Authorities launched an all-out search for the infant wrapped in a pink and blue blanket. The kidnapping attracted national attention, even featured on an episode of "America's most wanted." I want to know where my baby's at. I just want my baby back. Reporter: The case went cold for years. But her family never lost hope. I feel so strongly that mine is alive out there, mine is alive, somebody raising her like their own. Reporter: A hunch confirmed when two tips led investigators from Jacksonville, Florida, to Walter rose, South Carolina. Investigators be takened a DNA sample from her and last night received confirmation the young woman that we contacted in South Carolina is in fact kamiyah Mobley. Reporter: Court documents state Alex sister divided in a trend Williams told her about the kidnapping a year and a half ago. "People" magazine reports when Alexis asked for her birth certificate she needed to get a job, Williams broke down, finally telling her the truth. It is unclear why she kept the revelation a secret. After so many years of hoping and waiting, her biological parents made the trip to south rolina, meeting Alexis for the first time on Sunday. First meeting was beautiful. It was wonderful. Wouldn't have went no better. Reporter: Alexis seems all of it can seem overwhelming. Do you want to get to know them? I do. It is hard. But the love I have for my mother will never change. That's just it. I could get to know them and have the same love for them. She as victim of her mother's crime. And we need to really allow her to love whoever she wants to love. And to not make her feel guilty for having loyalty issues. Reporter: And there's heartache for the man who thought he was her father. I named her. That's the name I had for years. Reporter: Charles Manigo says his then-girlfriend Gloria Williams told him she gave birth to their daughter while he was away. Manigo and Williams raised her. The love of my life. Reporter: Tattooing her name on his arm. Celebrating milestones like prom. One of the hardest things since this was going on, Friday, "Dad, I love you." Even though she knows. There is pain for you knowing she's not going to be right next do you like that anymore? I've known her for 18, this will be the 19th year. You can't just -- that's a big part of my life. That's my heart. She made one mistake. But I was loved. Reporter: But that one mistake, a very costly one. The judge is going to have to balance the fact that this is a horrific crime. Stealing a child. And that 8-hour-old child is now testifying on behalf of the defendant. That will likely help her avoid a maximum sentence. But I don't think it's going to help avoid a serious and stiff sentence. In Lubbock, Texas, police and the FBI are looking for a woman they believe kidnapped a 3-day-old baby girl -- Authorities in bellflower, California, hope the following pictures will help them find a missing newborn -- Reporter: Baby abductions from hospitals are extremely rare. The national center for missing and exploited children reporting only 133 cases from 1983 to 2016. And the vast majority of them are found. That Alabama boy missing for 13 years discovered in Ohio -- Reporter: Rare cases, children find out about their own kidnappings years later. Authorities say the young man first became aware something was wrong when his social security number kept coming up invalid. Reporter: As they become young adults and need documents to apply for college and jobs, like Alexis did. Carlina was kidnapped and raised for 23 years as Nedra, but became suspicious and took matters into her own hands. I started typing into Yahoo! And Google different articles, like anything that pulled up from 1987, any child missing. Reporter: The once-broken family reunited. I just always believed she would find me. That was something that I always believed in myself. Reporter: Alexis' attorney Justin Bamberg says she will have to focus on the basics in rebuilding her life. Driver's license, social security number, birth certificate. The basic documents that someone needs to be an adult in America in 2017. Reporter: And any relationship Alexis is able to maintain with Williams, who could face life imprisonment if convicted will likely need to happen across prison bars. It's a long road. But Alexis can have two people who really love her and want her, and at the end of the day, that's a better story than being abandoned or unloved. Reporter: Still, Alexis unwavering in her dedication for the woman who kidnapped and raised her. I will never have hate towards her. I will always love her. Even though she did what she did? I will always love her. And there's the risk that you'll never have that same interaction with her again. I have memories. That will never die. Reporter: For "Nightline" I'm Eva pilgrim in Jacksonville, Florida.
This transcript has been automatically generated and may not be 100% accurate.