Sinister look from Levi troubled detective (4,3)
I believe the answer is:
evil eye
'sinister look' is the definition.
(I've seen this in another clue)
'levi troubled detective' is the wordplay.
'troubled' is an anagram indicator.
'detective' becomes 'eye' (as in a private eye).
'levi' anagrammed gives 'evil'.
'evil'+'eye'='EVIL-EYE'
'from' is the link.
(Other definitions for evil eye that I've seen before include "Indian sign?" , "Look that inflicts harm" , "Hex look" , "Look that can be harmful?" , "Look superstitiously believed to cause harm" .)