The Police perhaps claiming doctor is outlaw (7)
I believe the answer is:
brigand
'is outlaw' is the definition.
(I've seen this before)
'the police perhaps claiming doctor' is the wordplay.
'the police perhaps' becomes 'band' (I can't justify this - if you can you should believe this answer much more).
'claiming' is an insertion indicator.
'doctor' becomes 'rig' (both can mean to forge or manipulate).
'band' placed around 'rig' is 'BRIGAND'.
Can you help me to learn more?
(Other definitions for brigand that I've seen before include "Robber - darn big (anag)" , "thief" , "Marauder" , "desperado" , "Robber in wild places" .)