One leaving something in the kitchen covered in strontium, a killer (9)
I believe the answer is:
strangler
'killer' is the definition.
(I know that strangler is a type of killer)
'one leaving something in the kitchen covered in strontium a' is the wordplay.
I cannot quite see how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is located in the answer.
'something' could be 'er' (I've seen this in other clues) and 'er' is found in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'strontium' could be 'sr' (Sr is the chemical symbol for strontium) and 'sr' is present in the leftover letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for strangler that I've seen before include "Killer by choking" , "Murderer" , "Killer compressing the windpipe" , "he could take your breath away" , "criminal" .)