rebecca moen: i remember the shock of learning of her murder. she was alone and, you know, frightened. that's when i really first cried for brook, like really cried for her. greg winkler: brook's brother found her in her bedroom. she had been stabbed to death. dana winklepleck: she was a journalism major, editor of the school newspaper. it was so surprising that a 19-year-old college student would be murdered. and then there is a second student missing. and i was like, how could she be missing? i thought, that's not like erika. i knew something had happened, something bad. greg winkler: you could see blood on the walls, blood on the light switches. there was blood in the kitchen. bob dunham: i said, i think we have another murder by the same offender. hal johnston: they said, you need to catch this guy because he will probably strike again, and he'll be getting good at it. he was out there, just waiting. there's evil all around us. [theme music] hello, and welcome to "dateline." college students brook baker and erika norman were ambitious young

rebecca moen: i remember the shock of learning of her murder.