Seafood swindle requires private investigator (6)
I believe the answer is:
Here is my best explanation:
'seafood' is the definition.
(I've seen this before)
'swindle requires private investigator' is the wordplay.
'swindle' becomes 'scam' (scam is a kind of swindle).
'requires' says to put letters next to each other.
'private investigator' becomes 'pi' ('PI' can be a synonym of 'private investigator').
(Other definitions for scampi that I've seen before include "Edible crustaceans", "fish", "Large prawns cooked in batter", "Cooked Norway lobsters", "Type of seafood", "Breaded prawns", "Dish of fried shrimps or prawns", "Norway lobsters -- Dublin Bay prawns", "Dish of fried shrimp or prawns" and "Dish of cooked shrimps or prawns".)