US city prosecutors admitting everything (6)
I believe the answer is:
dallas
'us city' is the definition.
(I've seen this before)
'prosecutors admitting everything' is the wordplay.
'prosecutors' becomes 'D.A.s' (D.A. is an example).
'admitting' indicates putting letters inside (admit can mean to welcome in or accept).
'everything' becomes 'all' (all things).
'das' enclosing 'all' is 'DALLAS'.
(Other definitions for dallas that I've seen before include "Mysteriously, all sad in the US city" , "tragic city" , "Texan commercial city" , "oil centre" , "All sad at the disappearance of the long-running soap opera?" .)