A small point that gives some detective 'trouble' (6)
I believe the answer is:
detail
'a small point' is the definition.
(I've seen this before)
'some detective trouble' is the wordplay.
'some detective' becomes 'det' (abbreviation for detective).
'trouble' becomes 'ail' (synonyms).
'det'+'ail'='DETAIL'
'that gives' acts as a link.
(Other definitions for detail that I've seen before include "Specify" , "Particular - military detachment" , "Small detachment of troops or police on special assignment" , "Dilate on particulars" , "Select personnel - particular - group of soldiers" .)