Last three find addict and charge him with a crime (6)
I believe the answer is:
indict
'last' is the definition.
Although both the answer and definition are verbs in their base form, I can't see how they can define each other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for indict that I've seen before include "Charge (someone) with serious crime" , "Charge (someone) with a crime (mainly US)" , "Formally charge with a crime" , "To charge with offence" , "Accuse with a crime (US)" .)