Quickly pass to the suspect (9)
I believe the answer is:
posthaste
'quickly' is the definition.
(thesaurus)
'pass to the suspect' is the wordplay.
'suspect' indicates an anagram.
'pass'+'to'+'the'='passtothe'
'passtothe' anagrammed gives 'POSTHASTE'.
(Other definitions for posthaste that I've seen before include "Express" , "With great speed, like delivery of letters?" , "With utmost speed -- to the pass (anag)" , "at the double" , "Like Bat out of Hell" .)