(CNN) -- The man who says he was behind the Manti Te'o girlfriend hoax claims he was in love with the Notre Dame linebacker, but the athlete knew nothing about the ruse.
"He had no idea," said 22-year-old Ronaiah Tuiasosopo in the first segment of a two-part interview that aired Thursday on "Dr. Phil." The second part is scheduled to air Friday. "He did not know anything."
Asked if he was in love with Te'o, Tuiasosopo told host Phil McGraw:
"I mean, yeah ... as twisted and confusing as it may be, yeah, I cared for this person. I did all that I could to help this person become a better person, even though I wasn't getting nothing out of it. Of course, it's very shameful and it's very painful to even talk about. Even now, it's hard to talk about. But, you know, the truth of it is that that happened. I grew feelings. I grew emotions that, sooner or later, I couldn't control any more."
Asked whether he is gay, he said, "I would say, yeah, I am gay, but honestly, I am so confused, I'm so lost."
In the interview, Tuiasosopo said the relationship began after he started a Facebook page under the name Lennay Kekua, the first name an elision of his mother's and grandmother's first names and the last name one he had heard "thrown around in the neighborhood."
He said he "randomly added different people" as Facebook friends with the persona he had created. "One of the people I happened to add was his cousin," he said, referring to Te'o's cousin. "Shortly after, I got a friend request, and it was from Manti."
Tuiasosopo said he found out, as Lennay, that the gridiron star was in a relationship. "I never wanted to become a relationship wrecker or nothing like that," he said.
But that did not stop him; the relationship grew. They began speaking nightly, and Te'o seemed to have been smitten, too, Tuiasosopo said. "He really had fallen in love with this, we'll say, character."
Tuiasosopo said he and his younger sister met Manti in November, the night before Notre Dame's 22-13 victory over rival USC at the team's hotel.
"It was really awkward at first," he said. "I wanted to tell him everything right then and there." But Te'o's relatives intruded, and he decided it wasn't the right time, he said.
Tuiasosopo said his motives were pure; he never tried to make money off their relationship. "I just wanted to help him become better," he said.
The charade became difficult to maintain, and he tried to end it several times.
"There are many times where Manti and Lennay had broken up. But something would bring them back together, whether it was something going on in his life or Lennay's life, in this case in my life," Tuiasosopo said.
He added: "I wanted to end it because after everything I had gone through I wanted to move on with my life. Me, Ronaiah, I had to just start living and let this go."
Finally, after learning that Te'o had Skyped with four women -- including two of his former girlfriends -- Tuiasosopo said he essentially killed off Lennay, having her die of leukemia.
"I was just trying to do everything to end it because I knew that, no matter what, you know, it just wasn't right -- and it was never going to be."
A love story unravels
Thursday's segment is the latest revelation in what began as a story of one of the nation's best college football players leading his team to victory hours after learning his girlfriend had died, a story dismissed as a hoax after it was revealed Kekua did not exist.
Sports website Deadspin broke the story this month that the girlfriend whom Te'o, this year's Heisman Trophy runner-up, had talked about and had claimed died in September wasn't real.
Te'o rose to national prominence while leading Notre Dame's Fighting Irish to an undefeated regular season. As he and his team excelled, Te'o told interviewers in September and October that his grandmother and girlfriend, whom he described as a 22-year-old Stanford University student, had died within hours of each other.
"I miss 'em, but I know that I'll see them again one day," he said then.
An online relationship
Last week, Te'o told talk show host Katie Couric that Tuiasosopo had called him the day the story broke to confess.
During that interview, Te'o said he doubted the voice he knew as Kekua was a man's voice.
Tuiasosopo has said he faked his voice to sound feminine. In the interview, McGraw questioned his veracity and repeatedly challenged him to prove it.
McGraw said his show had contacted private contractors for the FBI and the Secret Service, giving them a voice mail message that Tuiasosopo said he had left for Te'o. "They looked at everything from voice intonation to tonal qualities" and concluded that "the chance that you are the person on that voice mail is like one in 10 million," McGraw said.
Tuiasosopo insisted he was telling the truth but said he would be uncomfortable talking in his feminine voice for the TV host. "I've never done it in front of people," he said.
Tuiasosopo' s state of mind
Psychotherapist Robi Ludwig said the behavior described by Tuiasosopo to McGraw is very possible.
"We see this with Internet dating. Sometimes people lie," Ludwig told CNN's Erin Burnett OutFront.
"It's a place where they can experiment and where they can impersonate the other sex."
Ludwig said it is possible that Tuiasosopo "actually did have a crush on Manti Te'o and was confused about his sexuality."
"And the reason why he impersonated this woman was to see what it would feel like to be intimate with Manti Te'o, to be loved by Manti Te'o," she said.
"Who would say this if it weren't true? I don't get the sense that he's a sociopath. I get the sense that he's confused."