Transcript for Former alt-right member wants to prevent others from joining these hate groups
When you're in there, you think that you just know the truth. White people are more intellectually capable than other people. Reporter: They are the words of a repentant racist. I start to use the phrasing and the language that there is an overwhelming majority of jewish people in media and thinking, you know -- you start to ask yourself, are jewish people white? Reporter: A young woman once consumed by hate. In that time did you think you were racist? I didn't. Looking back did you think you were? Yes. I never thought of myself as a racist person, but I was. Reporter: Samantha spent about a year of her life embroiled in a white supremacist hate group called identity europa. In the summer of 2017, identity europa united with other groups in a white supremacist movement and descended upon charlottesville, Virginia. Jews will not replace us! Reporter: It was a weekend filled with hate. One that would result in the death of a young woman, Heather Heyer, after rallygoer James Alex fields Jr. Deliberately drove his car into a group of counter protesters. Fields was sentenced to life in prison on federal hate crime Up until the unite the right rally, there was no explicitly connected death to the alt-right. And everything changed that day. Reporter: She realized it was time to get out. By the time I had left, there was the promotion of an ethno-state, the promotion of peaceful ethnic cleansing. There's nothing not hateful about that. Reporter: Samantha coming forward to warn others about the prevalence of hate and the means by which these groups bring others into their fold. People need to understand that it's not their in Wyoming who grew up with gas station beer and a toothless father who becomes this. It is your mailman, it is your surgeon, it is your doctor, lawyer, it is everyone. Reporter: Her story is included in the new book "Anti-social: Online extremists, techno-utopians, and the hijacking of the American conversation." I had talked to a lot of people in the alt-right at that point. She was one of the few people who was not in propaganda mode when she talked to me. So I felt like, rather than getting spin or what the movement wanted me to hear, I was just getting an actual human's story. Reporter: Samantha says while in the group she attended a few white supremacy events, like this one in the spring of 2017 held in D.C. Young people are not -- Reporter: There she is among the crowd listening to the words of alt-right founder Richard Spencer. Smntds that says it was rare for women to get involved. There was always at least like a woman at every party that I had gone to, other than me, but it was like a handful. They went to great lengths to make her feel important, because she was important, because they needed someone to be the female face of their movement. Reporter: Using a pseudonym, Samantha says she became very active in the group's online chat rooms. Did you ever post hateful messages? Probably. I don't specifically recall, but I probably did. Sounds to me like when a politician is asked, did you ever pose in blackface? Either you did or didn't. I don't know. I say that in the sense that I haven't looked back, but I probably did. Reporter: But her participation grew darker. I remember I was at a party. In walks one of the leaders of the movement. He said, seig -- pretty much everyone raised their hand and said, heil. Including you? Eventually, yeah. It happened one or two times. By the third time, I did it. I knew that it wasn't -- it was not a good look, but I did it. Everyone else was doing it. Reporter: That kind of thinking, putting aside one's morals to follow in the footsteps of others, is perhaps what got Samantha involved with white supremacy in the first place, she so badly wanted to feel like she belonged. I came to the realization instead of accepting I'm a generally mediocre person, those groups make you feel like you are excellent, you are it, just for existing, for doing absolutely nothing. You're making it sound like, if you're a member of one of these groups, the qualifications are, be white and be a loser. I can't argue that. It's easier to get sucked in if you're lonely, if you don't have a strong sense of self. I think they got to her at a time in her life when she was just really battered around, didn't really know who she was. Reporter: She was a girl who grew up in the suburbs of new Jersey, middle class as she describes it. A nice disguise for family demons. My brother and I were trying to raise ourselves. In the middle of high school, I moved to Florida. I just felt like a total and complete alien. How do we get from there to where you went next in your life? I met someone in 2014 that I immediately fell in love with and that was that. It was game over. Reporter: But Samantha says one day, that all changed. When he changed. He'd become a degenerate. He started saying phrases like, he couldn't defend me on the day of the rope. Day of the rope? What is that? Day of the rope is -- whoo. The day of the rope is the day as written in the turner diaries where white people, as a race, take people that they have deemed degenerates, unworthy, people of color, people with disabilities, people that are gay or whatever, whatever is deemed unpure, unfit for the white race, and they drag them out of their houses and they hang them by lamp posts. The turner diaries sounds like a hymnal for Adolf hitler. Yeah. I mean, it was found in Timothy Mcveigh's car after the Oklahoma bombings. Where do you go from there? I confronted him and just asked him like, what is all of this stuff? And he looked me dead in the eye and just said, I think I'm a fascist, and I don't want to be with anyone who can't support and then I packed up whatever I had with me and left. And I was crying. By the time I got to my house I was like, I need to understand it, though, like where did this come from? Reporter: She says she spent the next five days scouring the internet for information in an effort to convince herself that her boyfriend wasn't racist. A few days later she calls him. And I tell him, I'll try and understand this with you. And so I start consuming more media. Were all these videos No. I mean, a lot of it was, here's a baking show with this woman who is dressed like a traditional woman on a prairie. She's really smart, but she didn't know enough to know the things that were talking points and the things that were propaganda and how to push back against them with reality. Reporter: Soon after she joined that group, identity europa. Soon after I joined I thought it was pro-white, I didn't think about what it really was. It really is what? A hate group. It's absolutely a hate group. In your words you were pro-white. Did that mean you thought less of people who look like me? No, I didn't think I did. Either you're pregnant or you're not, right? That's something I've struggled to come to terms with, but I didn't think I was doing anything wrong. Reporter: Identity europa has rebranded themselves as the American identity movement. That according to the anti-defamation league. A lot of these groups, they constantly have to rebrand. Because they have such a terrible actual belief system, that once people find out what the belief system is, they have to keep shifting. But the core of it is the same. Reporter: On its website it describes itself as an organization that displays defiance against mass immigration and globalism, prohibit the advocacy or participation in supremacy, violence, or illegal activity. They say allegations to the contrary originate from left-wing individuals and organizations. As for Samantha, today she lives with both fear and regret. Fear of those she followed. Regret for those such hate can I learned from this, and I really hope I can help people understand how this happens and how they too can get out, and how maybe you can even stop someone from starting. Reporter: For "Nightline," I'm Byron Pitts. Our thanks to Byron for that
This transcript has been automatically generated and may not be 100% accurate.