Originally Posted by VidaRed

taken from lost forum

Some of the theories regarding Ji Yeon and Jin's death?
Theory 1:
Jin's segment in the show was in fact a flashback. This suggests that Jin does die and it also explains him saying that he had only been married for 2 months.
This idea can also be backed up by Jin's tombstone which says DOD was the day flight 815 crashed suggesting he never made it off the island, however, the writers said we would know all of the oceanic six by now. Perhaps, it is a red herring and the introduction of Michael is exactly that. Is he the sixth member? The most likely contender is Aaron.
Probability: 90%