Killed in turn (4)
I believe the answer is:
slew
This clue is a double definition.
'killed' is the first definition.
(historical past tense of slay)
'turn' is the second definition.
(slewing is a kind of turning)
'in' is the link.
(Other definitions for slew that I've seen before include "Move obliquely or sideways, often losing control" , "Greatly amused" , "a large number in America" , "Killed long ago" , "Killed in literary way" .)