Murdered a large number (4)
I believe the answer is:
slew
This clue is a double definition.
'murdered' is the first definition.
(archaic past tense form of 'slay')
'a large number' is the second definition.
(slew can mean a large amount of something)
(Other definitions for slew that I've seen before include "Killed in literary way" , "Killed long ago" , "Butchered" , "Slide uncontrollably" , "Killed - swing" .)