Criminals show disadvantages of scams (4)
I believe the answer is:
cons
I believe this clue is a triple definition!
'criminals' is the first definition.
(short for convicts)
'show' is a link.
'disadvantages' is the second definition.
(as in pros and cons)
'of' is a link.
'scams' is the third definition.
(I've seen this in another clue)
(Other definitions for cons that I've seen before include "Swindles" , "Tricks" , "Arguments against" .)