a nice person? i mean, nikki was such a good person. >> the hardest question always the why. the coldest fact, the young woman gone too soon. >> that's all for this edition of dateline. i'm craig melvin. thank you for watching. >> i see her laying there on the floor. and i see a person i've never seen before in my house. and i'm looking at him and he tells me i'm next while he's reaching for a butcher knife. terrified. >> i just walked in and i saw blood everywhere. it was her mom who found her. >> her daughter's laying there. a young girl coming home from lunch getting brutally attacked. >> blood on the floor. a shovel. duct tape. a knife. >> i rushed home. i truly thought brittani would die.