>> yes. >> do you think your brother killed tricia reitler? >> yes. >> rihanna rison? dewey? >> yes. >> as gary started talking more openly, detectives approached him asking for help. >> i went with the indianapolis detectives down to try to get my brother to confess. he made me leave the room. he did in fact confess on tape to 15 serial murders. >> larry later retracted again. and while he can't ever seem to stick to one story, he does sometimes seem to have regrets. >> i didn't want to keep living my life the way i was living it. i wanted things to be different, you know, but i guess i didn't really do the right things to change the way my life was going. >> larry hall refused our request for an interview. he has never been charged with crimes against anyone other than jessica roach. but keene's story has caused officials across the country to take another look at hall. >> in november of 2010 investigators from the police department interviewed mr. hall at a prison in north carolina. >> in that interview hall admitted murdering laurie de pughs and provided clues to f