Veteran detective that monitors criminal in new role (3,6)
I believe the answer is:
old stager
'veteran' is the definition.
(I know that veteran can be written as old stager)
'detective that monitors criminal in new role' is the wordplay.
'detective' becomes 'DS' (detective sergeant).
'that monitors criminal' becomes 'tag' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'new' is an anagram indicator.
'ds'+'tag'='dstag'
'role' anagrammed gives 'oler'.
'dstag' put inside 'oler' is 'OLD STAGER'.
Can you help me to learn more?
(Other definitions for old stager that I've seen before include "expert" , "One who's experienced a lot" , "senior citizen" , "veteran" .)