when kathy heckel disappeared, police >> hello "dateline". when kathy disappeared, police did not know if they were dealing with a missing person case or cold-blooded murder. with little evidence to go on, the investigation grew cold. decades later, a young detective who was just a kid when kathy vanished dusted off the old files. investigators could not solve her case then. could he help solve it now? >>> time can be like a river, a long stream of events, rushing by. most barely make a ripple, but few, like the sudden loss of a close friend, a child, or apparent, have a way of circling back upon us in a ceaseless wave of memory and regret. that's the way it's been for john and his sister, alicia talbot, since the completely normal morning in 1991 when their mom, kathy, kissed them goodbye, left for work, and never returned. >> you remember her leaving that morning? >> yes. like any other day. same routine, all the time, every time she left us, she kisses goodbye. >> it was a july morning. alicia was 13 and john was nine , home for summer vac