Killer in position in Jamaica (5)
I believe the answer is:
ninja
'killer' is the definition.
(I've seen this before)
'in position in jamaica' is the wordplay.
'in' says the answer is hidden in the clue.
'NINJA' can be found hidden inside 'position in jamaica'.
(Other definitions for ninja that I've seen before include "Japanese trained assassin" , "Teenage Mutant -- Turtles (TV/film)" , "Deadly type" , "Old professional Japanese assassin" , "Ninjutsu expert" .)