Abhor detective's case, pre-trial (6)
I believe the answer is:
detest
'abhor' is the definition.
(I've seen this before)
'detective's case pre-trial' is the wordplay.
'case' says to hollow out the word (remove centre letters).
'pre' says to put letters next to each other ('pre' means before).
'trial' becomes 'test' (synonyms).
'detective' with its centre removed is 'de'.
'de'+'test'='DETEST'
(Other definitions for detest that I've seen before include "'Loathe, abhor (6)'" , "Abominate" , "Loathe, hate intensely" , "Greatly hate" , "Cordially laothe" .)