Imprisoned grass admits bloke died (8)
I believe the answer is:
remanded
'imprisoned' is the definition.
('remand' can be a synonym of 'imprison')
'grass admits bloke died' is the wordplay.
'grass' becomes 'reed' (I've seen this before**).
'admits' indicates putting letters inside.
'bloke' becomes 'man' (I've seen this in other clues).
'died' becomes 'd'.
'man'+'d'='mand'
'reed' enclosing 'mand' is 'REMANDED'.
(Other definitions for remanded that I've seen before include "Held in custody, or on bail, pending hearing" , "Placed a defendant on bail or in custody pending trial" , "Imprisoned" .)