Murderer maybe near the stern in rescue float (4,4)
I believe the answer is:
life raft
'rescue float' is the definition.
'life raft' can be an answer for 'float' (life raft is a kind of float). I am not certain of the 'rescue' bit.
'murderer maybe near the stern' is the wordplay.
'murderer maybe' becomes 'lifer' (I can't explain this - if you can you should give a lot more credence to this answer).
'near the stern' becomes 'aft' (I've seen this before).
'lifer'+'aft'='LIFE-RAFT'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for life raft that I've seen before include "Flat float for emergency at sea" , "emergency transport" , "Inflatable emergency craft" , "Rescue vessel" .)