the strange disappearance of carrie olson. >> it was scary. everyone loved carrie. >> it was so painful. >> you reach out to dateline? >> i did, yes. we started getting people following our page. >> where was she? what was behind this? far from home early. >> i saw the tattoo and i said, that's her tattoo, isn't it? >> and three caught on camera clues. someone's in her car. someone's at her back. but, most jaw-dropping of all, someone is up onstage with a song turned sinister. >> i couldn't believe what i was hearing and seeing. >> could karaoke be a key to this case? >> my heart was pounding and pounding. >> i was sweaty and nervous. we need to figure this out, fast. hello, and welcome to dateline. 29 year old carrie olson was the girl next door, bubbly and bright, with close friends and a new man in her life. she had everything ahead of her, and then she vanished. had she just walked away, or did someone take her? was she even alive? here is andrea canning and without a trace. >> it is a sad fact of american life, family separated from their