>>> the latest chapter in the manti te'o girlfriend hoax. the man behind the deception is now explaining why he did it and how. here's nbc's kristen dahlgren.
>>> i don't want to be.
>> reporter: as ronaiah tuiasosopo, the man behind the manti te'o hoax, answered dr. phil's questions --
>> people say, does he have any feel being this, the truth is i hurt every day from the decisions i made.
>> reporter: he admitted he was motivated to create the fake girlfriend because of his own romantic love for the football star and a painful past.
>> i want to talk about why you felt moved to create an alter e ego.
>> it went through what i went through as a child.
>> reporter: it took the tv psychologist several tries to get an answer to one of most perplexing questions -- was it really tuiasosopo alone who left the voice dmalmails.
>> i want the truth.
>> reporter: he first went behind a screen to do the voice.
>> i love you so much, sweet dreams .
>> reporter: the show was analyzed by experts.
>> 87%, 40%, 48%. not conclusive.
>> reporter: they sent a producer to tuiasosopo's house where he said he made the calls in private. whe with the producer's phone he recorded this.
>> sweet dreams .
>> this time there was no question -- match, match, match.
>> reporter: perhaps conclusive proof. but for many, still not enough. even with this public apology to manti te'o.
>> i can never express how sorry i am.
>> reporter: for what appears to be simply a cruel hoax that fooled a young star and has fascinated a nation. for "today," kristen dahlgren, nbc news, los angeles .