keith morrison: the year was 2004, and aaron candelario was 11 years old. recently separated, were sharing custody. but one day, after a weekend at his dad's house, aaron went home to find-- there was just a note on the coffee table that was in kind of sketchy handwriting. but it nevertheless said i love you, my boys, and i'm taking off. keith morrison: his mother dena was simply gone. aaron was devastated. what did your father suggest may have happened to her? that she possibly had moved to missouri. a guy that she had been talking to online for quite some time, you know, maybe she ran away to be with him. keith morrison: a missing person's case was opened, but nothing came of it. aaron and his brother moved in with ralph full time. but aaron couldn't move on. she had to have left some trail somewhere. barely a teenager, he taught himself every web search engine, looked for years, but found no sign of his mom online. and a terrible suspicion took hold of him, hardened into do something like certainty-- his mother must be dead. his father must have done it.