Behold: Detective Inspector's flipping hero (4)
I believe the answer is:
idol
'hero' is the definition.
(I've seen this before)
'behold detective inspector's flipping' is the wordplay.
'behold' becomes 'lo' (archaic exclamation meaning 'look!').
'detective inspector' becomes 'DI'.
'flipping' says the letters should be written backwards.
'lo'+'di'='lodi'
'lodi' written backwards gives 'IDOL'.
(Other definitions for idol that I've seen before include "someone admirable" , "Figure of worship" , "Hero of screen or stage" , "Personal hero" , "Person who is the object of intense admiration as by fan club" .)