Person in charge round street is thief (7)
I believe the answer is:
rustler
'is thief' is the definition.
(I've seen this before)
'person in charge round street' is the wordplay.
'person in charge' becomes 'ruler' (I've seen this before).
'round' is an insertion indicator.
'street' becomes 'st'.
'ruler' placed around 'st' is 'RUSTLER'.
(Other definitions for rustler that I've seen before include "lawbreaker" , "Cattle stealer" , "Livestock thief" , "Cattle thief" , "one whose stock-taking is dishonest" .)