Partner in fracas - so CIA testifies (9)
I believe the answer is:
associate
'partner' is the definition.
(thesaurus)
'in fracas so cia testifies' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ASSOCIATE' is hidden within 'fracas so cia testifies'.
(Other definitions for associate that I've seen before include "Partner in work or business" , "Person one works or spends time with" , "Get together with" , "Make a logical or casual connection" , "Partner, colleague" .)