Removed all the crooks? (12)
I believe the answer is:
straightened
'removed all' is the definition.
The answer and definition can be both related to change as well as being past participle verbs.
Maybe they are linked in a way I don't understand?
'the crooks?' is the wordplay.
I cannot quite see how this works, but
an anagram of 'the' is 'hte' which is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for straightened that I've seen is " Put in order".)