The family’s grief is for a thirteen-year-old, for the child they knew and lost.

But if Nicholas is alive somewhere — if the runaway theory is correct and he is living under another identity, or if he escaped some harm that befell him — he is not a thirteen-year-old.

He is a middle-aged man with thirty years of life that his family does not know about.

The hypothetical versions of Nicholas Barclay that exist in the minds of the people who knew him — the teenager he was, the adult he might have become — are themselves a dimension of the loss that long-term missing persons cases create.

Cold case investigators who look at long-unresolved disappearances sometimes focus on this dimension: what would this person look like now?