welcome back. for 15 years, judy carlson has been haunted by the disappearance of her son, david. now, detective donna velasquez was reaching deep into the past for clues. there she found the tale of two love-struck teenagers who married, had a baby, and divorced in quick secession. common sense and an exhaustive internet search were about to lead the investigator to a stunning discovery. here again is keith morrison. >> it was june 25th, 1988, ft. lauderdale, the day the mystery began. when a young man named david jackson failed to meet his brother, mark, at the airport. >> it was a gut feeling