Finder of missing persons (6)
I believe the answer is:
tracer
'finder of missing persons' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tracer that I've seen before include "beast to tow" , "This bullet leaves smoke in its passage" , "ammunition" , "Kind of bullet that leaves trail" , "Type of bullet or shell" .)