Former cop journalist blasted (8)
I believe the answer is:
exploded
'blasted' is the definition.
(a blast is an explosion)
'former cop journalist' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'cop' becomes 'plod' (plod can informally mean a police officer).
'journalist' becomes 'ed' (short for editor).
'ex'+'plod'+'ed'='EXPLODED'
(Other definitions for exploded that I've seen before include "Blew up" , "Burst violently" , "Blown up - no longer valid" .)