I'm trying to find out what the families of captured U.S. military servicemen would have known in 1968 of their status. As far as I can tell, not many families would have definitely known they were alive and in POW camps. Were servicemen classified as MIA? I know the U.S. knew about John McCain, because the North Vietnamese found out his father was important and so released information about his capture, but I'm thinking of the regular pilots without influential families. thanks!