Defendant: 'PC set us up!' (7)
I believe the answer is:
suspect
'defendant' is the definition.
('suspect' can be a synonym of 'defendant')
'pc set us up' is the wordplay.
'up' is an anagram indicator.
'pc'+'set'+'us'='pcsetus'
'pcsetus' anagrammed gives 'SUSPECT'.
(Other definitions for suspect that I've seen before include "One thought to have committed crime" , "Imagine to be guilty" , "man distrusted?" , "One thought guilty of a crime" , "Hazard a guess" .)