Criminal in photo stealing books possibly over forty, by the looks of it (4,2,3)
I believe the answer is:
thin on top
'over forty by the looks of it' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'criminal in photo stealing books' is the wordplay.
'criminal' is an anagram indicator.
'stealing' is an insertion indicator.
'books' becomes 'NT' (abbreviation for New Testament).
'in'+'photo'='inphoto'
'inphoto' is an anagram of 'thinoop'.
'thinoop' enclosing 'nt' is 'THIN ON TOP'.
'possibly' is the link.
Can you help me to learn more?
(Other definitions for thin on top that I've seen before include "showing scalp?" , "State of advancing baldness" , "not so hairy now" , "developing a shine for the Head?" , "Result of losing hair, balding" .)