WASHINGTON — Cydney Mizell, an aid worker teaching English in southern Afghanistan, vanished in 2008, abducted after being driven off the side of a road and presumed dead for 15 years. Members of her family, left with few other details of the circumstances surrounding her disappearance, wondered whether they would ever learn her fate. Jan Mizell, her younger sister, said she would tell people: “Somebody over there knows what happened to my sister. They’re just not talking.” Sign up for The Morni