Killed in Los Angeles during wickedness (5)
I believe the answer is:
slain
'killed' is the definition.
(slaying is a kind of killing)
'los angeles during wickedness' is the wordplay.
'los angeles' becomes 'LA' (abbreviation).
'during' means one lot of letters goes inside another.
'wickedness' becomes 'sin' (synonyms).
'la' put within 'sin' is 'SLAIN'.
'in' is the link.
(Other definitions for slain that I've seen before include "Killed, murdered" , "Slaughtered" , "Put to the sword" , "Violently killed" .)