Crime ran so wild! (5)
I believe the answer is:
arson
'crime' is the definition.
(I've seen this before)
'ran so wild' is the wordplay.
'wild' indicates an anagram.
'ran'+'so'='ranso'
'ranso' with letters rearranged gives 'ARSON'.
(Other definitions for arson that I've seen before include "Pyromaniac's crime" , "Sonar (anag.)" , "Torching" , "matchplay, say?" , "A burning crime" .)