Hammer everybody in police force (6)
I believe the answer is:
mallet
'hammer' is the definition.
(I know that mallet is a type of hammer)
'everybody in police force' is the wordplay.
'everybody' becomes 'all' (I've seen this before).
'in' indicates putting letters inside.
'police force' becomes 'met' (short for Metropolitan Police Service).
'all' placed within 'met' is 'MALLET'.
(Other definitions for mallet that I've seen before include "Croquet stick" , "Used to beat" , "Small wooden hammer" , "stick in Polo" , "Hammer for pegs or croquet" .)