in her first interview. why did you want to do this? it s just an important time to speak up. reporter: powerful new d i details with a warning. at times they can get graphic. i know it s hard to tell this story. yes. it s hard, gianna, for you to hear this. reporter: and a powerful confrontation with bill cosby himself. i was yelling and saying to him, you re sick. reporter: one woman, standing for them all. shero, joan of arc. she took us from victim to survivor. i just needed to make the first step.ooiv after that, it was in god s hands. hello. and welcome to dateline. for years andrea constand
i think you just need to go and relax on the sofa. and so i i got up. and when i got up, my legs were very weak. could you walk? no. i could not walk. he supported me over to the the sofa. he lays you down on the sofa? yes, he does. what s the next thing he puts you remember? a pillow under my head. i just remember walking over there. he placed a pillow under my head. and he said, just lay down there and relax. and so i laid on my side. and i passed out. i know it s hard to tell this story. i know yes. it s hard, gianna, for you to hear this. uh-huh. andrea constand described in explicit detail what bill cosby did to her neck. her mind may have been hazy from those three pills, but what happened is clear. she was sexually assaulted.
what s that phone call like? well, it was a two and a half hour conversation. what was your tone? well, i was very, very angry. very, very angry. reporter: throughout the call, she says, he called her mom. he tried to lead her to believe the sexual act with andrea was consensual. it was a lot of game playing, a lot of manipulation, my conversation with him. and i think when i said to him, you know what? i said, it s it s best you re truthful. it s best you re honest. reporter: gianna says cosby asked to have andrea pick up the other line. she did. and they say he made a startling admission. he said, i m sorry, andrea. and i m sorry, mom. reporter: gianna wasn t having it. i was yelling and saying to him, you re sick. you re a sick man and that, he he agreed. he said that he was a sick man. he agreed?
his admission of what he had told me on the first call. i wanted to get back to you because reporter: but right away, it seemed cosby wasn t willing to talk about what happened to andrea. i i don t wanna talk about anything except a mute, a mutual feeling for uh, a friendship. reporter: and just as fast, gianna s plan started to unravel. cosby seemed to realize she was recording the call. so gianna tried to make an excuse for a sound he heard. blaming it on her pet. you do you have a beeping going on on your phone? no, no, not at all. i have a parrot. i know this is a beep. no, no. i have a parrot. i mean i don t have a no. a parrot? reporter: cosby changed the subject and offered to financially help andrea if she wanted to pursue a graduate degree. yeah, i ll lay out what i think is the best. pay for the schooling.
uh-huh. and a whatever, as long as she maintains a 3.0 average, she ll be fine. reporter: gianna says she wasn t interested in cosby s bun, but she did want the name of the drug he d given andrea. she d asked him for that in their previous phone call. are you really going to send me on that piece of paper the name of that stuff or not or were you joking? oh, no, no, no, no. we can, we can talk about what you asked for later. okay. okay. okay, just because i m concerned. i, i don t know how it affected her and i wanna know. i don t think so. i wouldn t even worry about it if i were i m serious about this. let s get with the other thing. okay? reporter: the conversation ended. days later, andrea was interviewed by police in pennsylvania.