Intelligence to capture terrible hound in murder mystery (8)
I believe the answer is:
whodunit
'murder mystery' is the definition.
(I know that whodunit is a type of detective fiction)
'intelligence to capture terrible hound' is the wordplay.
'intelligence' becomes 'wit' (wit is a kind of intelligence).
'to capture' indicates putting letters inside.
'terrible' indicates an anagram.
'hound' with letters rearranged gives 'hodun'.
'wit' enclosing 'hodun' is 'WHODUNIT'.
'in' acts as a link.
(Other definitions for whodunit that I've seen before include "'A crime novel, colloquially (8)'" , "Question commonly posed" , "murder investigation" , "thriller" , "Informally, a detective story or play" .)