Selected by Michael W.: Roger Ellison, a seventeen-year-old senior who vanished from Cedaredge, Colorado on February 10, 1981. (I should have done this last Sunday. My apologies.)
Although many kids disappear en route to or from school, it seems very few of them actually disappear on the school campus itself. Roger did: he definitely made it to school that day, and was sighted putting stuff in his locker in the morning, but never attended class.
His case is classified as a non-family abduction and police believe he was killed shortly after he went missing. And there is someone the cops have in mind, a person of interest.