. >> she vanished one october afternoon, ten year old amy mihaljevic. >> is amy there? is amy? there she never came home from school. >> she's got to meet somebody, go buy a present for her mother. >> whatever is wrong, come home. >> it's been a mystery for more than 30 years. who took amy? >> these are photos of a lot of your evidence. >> now, investigators are opening their files to us. >> this is more like you're ted bunny guy. >> correct. >> and you'll get the chance to help crack this case. >> we want to hear for you. >> just called with that new piece of information. >> pick, and pick, and pick, and boom, it solved. >> there is still a killer out there. and somebody has to know something. ♪ ♪ ♪ >> hello, and welcome to "dateline". never stop investigating until the mystery itself. that's the mission of detectives determined to crack the canavan case of amy mihaljevic. there are many clues, and though decades have passed, the trail of evidence has not grown cold. so, police decide to do something rare, ask for your help to answer a burning question. here's josh mankiewicz

. >> she vanished one october afternoon, ten year old amy mihaljevic. >> is amy there? is amy?her mother. >> whatever is wrong, come home. >> it's been a mystery for more than 30 years. who took amy?