Detective's bloomer leads to tragedy (8)
I believe the answer is:
disaster
'tragedy' is the definition.
('disaster' can be a synonym of 'tragedy')
'detective's bloomer' is the wordplay.
'detective's' becomes 'dis' (Detective Inspector).
'bloomer' becomes 'aster' (aster is a kind of flowering plant).
'dis'+'aster'='DISASTER'
'leads to' acts as a link.
(Other definitions for disaster that I've seen before include "Great tradegy or cataclysm" , "Tragedy of asterids" , "terrible trouble" , "complete failure" , "Catastrophe, tragedy" .)