Police officer at end of case examining body (12)
I believe the answer is:
inspectorate
'examining body' is the definition.
(I've seen this before)
'police officer at end of case' is the wordplay.
'police officer' becomes 'inspector' (inspector is a kind of police officer).
'end of case' becomes 'e' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'inspector'+'at'+'e'='INSPECTORATE'
Can you help me to learn more?
(Other definitions for inspectorate that I've seen before include "examining body" , "custodians" , "Regulatory organisation" , "Members of OFSTED" , "Examining official's office" .)