Fraud involving violin (6)
I believe the answer is:
fiddle
I believe this clue is a double definition.
'fraud' is the first definition.
(I've seen this before)
'violin' is the second definition.
(I know that violin can be written as fiddle)
'involving' acts as a link.
(Other definitions for fiddle that I've seen before include "Cook" , "Play - cheat" , "Swindle with informal violin" , "something stringy?" , "Fit as a . . . . . . - in good musical shape?" .)