PC swap in Prime Suspect investigated for this (5)
I believe the answer is:
crime
'suspect investigated for this' is the definition.
(someone may be suspected of a crime)
I don't understand the remainder of the clue.
(Other definitions for crime that I've seen before include "Violation of law" , "An act punishable by law" , "Punishable deed" , "Illegal deed" , "A serious offence" .)