Crime-fighter's leaving it in disarray (9)
I believe the answer is:
vigilante
'crime-fighter's' is the definition.
(I've seen this before)
'leaving it in disarray' is the wordplay.
'in disarray' indicates anagramming the letters.
'leaving'+'it'='leavingit'
'leavingit' with letters rearranged gives 'VIGILANTE'.
(Other definitions for vigilante that I've seen before include "Man on patrol" , "Self-appointed lawman" , "Policeman unofficially" , "Unauthorised law enforcer" , "Sort of PC not formally recognised" .)