>> reporter: i got to say, by the way, don't want to embarrass you, but i have found that investigators of homicides are the biggest softies on the planet. >> we're not supposed to let that out, but once in a while it happens. >> reporter: you're not supposed to care as much as you do, but you really do. >> you do. >> oh, absolutely. >> you become very attached. >> those girls are special. pam had a part in that, and they're -- hopefully they'll be able to live on her legacy. >> reporter: and ralph's legacy? because of him, aaron will go on searching, hoping to learn what happened to his mother. >> yeah. i will be looking. probably in -- oh, in some way my entire life i'll always be asking questions. >> reporter: and shannon -- >> he needs to realize this isn't over. he didn't just murder someone and have nothing afterwards. he left behind family. he left behind a disaster. and if i'm the only thing to remind him of that, then that's what i'm there for.