>> i always loved david. >> -- or just maybe a black widow? >> barbara britton is in the middle. >> "buried clues." hello and welcome to "dateline extra." i'm craig melvin. the case sat cold for more than a decade, and then rookie detective donna velasquez got the file and turned up the heat. she'd been given the basics. 24-year-old divorced dad david jackson had vanished without a trace. digging into david's past, she uncovered a twisted tale of love gone bad and a chilling family secret. but to learn the full truth behind david's disappearance, the detective would have to sort the players from those getting played. here's keith morrison. >> it's a strange thing that happens among the bogs and marshes, the soft soil here in coastal florida. things have a way of coming up.