Back sometime in the mid-80s, we we treated to this set up in many of the Marvel titles.
Peter is supposed to do a news story on a VIP only to find him missing.
So he goes back as Spider-man to investigate, find a clue, and says he's going to track him done.
http://i.imgur.com/J8aG3W4.jpg?2
http://i.imgur.com/x9uawW2.jpg?1
This isn't addressed again until a year later when we find the villain that may be responsible. The story never says, but it's likely.
http://i.imgur.com/bkc3s00.jpg
And since then... nothing. The plot cuts off in mid-supervillain confrontation and has never been resolved. Isn't it time we got some resolution on that?