. >> reporter: laura nirider of northwestern university's innocence project is a leading expert in false confessions by young people. she represents brendan dassey of "making a murderer" fame. nirider heard about robert's case and offered to help. and help us understand what happened to robert, as we watch the interrogation unfold. >> reporter: randy snead -- a man robert has long trusted begins the interview at 2:00 am, by which time robert has been awake 18 hours. >> never been in that house? >> no. >> reporter: again and again, more than 70 times. >> start telling the truth. >> i am. >> reporter: robert insists he is innocent. >> i had nothing to do with this. i swear to god. >> reporter: nine times, robert asks for a polygraph. >> i will take a polygraph test right now. i am being honest. i will take a polygraph test. i have said that how many times? >> officer snead, i was not there. i will take a polygraph test right now to prove to you that i was not there. >> when you've got somebody in the interrogation room who offers to take a polygraph, that's a strong sign of innocence that

. >> reporter: laura nirider of northwestern university's innocence project is a leading expert in falsessions by young people. she hurt about raurert's case and offered to help. and help us understand what happened to robert as we watched the interrogation unfold. >> this is one of the most intense interrogations i have ever seen. >> anything you cay can and will be used against you. >> you have these officers very, very close to robert who is a big guy, pushed into the corner, increasing the pressure without touching him. >> randy, a man robert has long trusted, begins the interview at 2:00 a.m., by which time robert has been awake 18 hours. >> never been in that house? >> no. >> again and again, more than 70 times. >> start telling the truth. >> robert insists he is innocent. >> i had nothing to do with this. i swear to god. >> nine times robert asks for a polygraph. >> i will take a polygraph test right now. i'm being honest. i will take a polygraph test. i have said that how many times. i was not there. i will take a polygraph to prove to you i was not there. >> when you have somebo

. >> which, said laura nirider is about the least robert deserves.n prisons who confessed under duress. to something they didn't do. >> slowly, these stories are beginning to make headlines, and so now we see, eyes are beginning to open, questions are beginning to be asked around the country. and that is what happened in robert davis' case. >> one night of your life made a hell of a difference, didn't it? >> yeah. yeah. >> you know, it's a small town. do you ever run into randy snead? >> he lives here. but i haven't run into him. if i was to see him walking down the street, i would probably just keep walking, because i don't really have nothing to say to him. except for i told you so. i told you that i was innocent. >> so he was. so he is. >> that's all for this edition of "dateline extra." i'm tamron hall. thank you for watching. xxxxx . ♪ >>> he was definitely charismatic. he lived every single day. he knew that it was dangerous, but no one ever knew that someone would die over it. >> he was the new kid in town, super popular. all about adventure.